"

-- ~-~-~ ~--,----------------...,

Indian Journal of Radio & Space PhysicsVol. IS, October & December 1986, pp. 367-374

Evolution of Research on Electron Devices in India

S DEB

School of Energy Studies, Department of Electronics & Telecommunication Engineering, Jadavpur University, Caleutta

This review seeks to give a broad coverage of the research efforts in the field of electron devices inIndia. Starting with the earlier work in the field by Sir J.C. Bose, the pioneering effort of Prof. S.K. Mitrain initiating systematic work on electron tubes is recalled. The tourse of events following the advent ofthe semiconductor age is outlined giving brief accounts of the activities in some of the NationalLaboratories, research institutes, industries, the IITs and the universities. The roles of the principalfunding agencies are discussed. The importance of more intensive and purposeful approach, greaterinteraction between industries and research organizations, better appreciatitm of the key rote of basicinvestigations on development of new devices, a.re etpphasized.

1 Introduction

The story of Professor S.K. Mitra's tireless efforts inthe thirties in introducing Radio and WirelessCommunication as a subject of higher studies andresearch in India, is well known., Apart from theactivities initiated in his own laboratory at Calcutta, heprevailed upon the Government of India to constitutea Radio Research Committee to organize acoordinated programme of work in the country1.Later on, as the custodian of the Committee, heplanned a concerted chain of Rand D projects aimedat attainment df self-reliance in respect of vitalelectronic components. The most ambitious of thesewas the one relating to electron tubes. He carried theblueprint of the project with him while on a trip to theU.K. and the U.S.A., as a member of the IndianScientific Delegation towards the end of 1944, locatedthe sources of supply of important equipments,materials and literature for the project and had thesame sanctioned by the CSIR early in 1945,immediately after his return. It took about a year forthe equipment to arr.ive and the project was actuallylaunched in April 1946. It marked the beginning ofresearches on electron devices as a distinct area ofactivities in India. The present paper seeks to cover thestory of its growth since then, although, for the sake ofcompleteness, a reference to some earlier effort in thefield is certainly called for.

2 The Phases of Growth

The growth of research on electron devices in Indiahas taken place in a number of distinct phases. Theseare depicted broadly in Fig.1. The pre-1946 activities

may be treated as the early phase. The launching oftheproject referred to above, in 1946, marked thebeginning of the vacuum tube phase which continueseven now-undergoing changes in complexion withtime. Superimposed on this, from 1960onwards, is thephase related mostly to the transformation brought

about by various technological advances in the solidstate family of devices, preceded by a rather briefintermediate phase, during the 1955-60, marking anera of activities preparatory to the former. Thesevarious phases are described in the next few sections.As the activities in the earlier years (1946-65) arecomparatively less known at the present time, a morecomplete account will be attempted for this period.

21 1be Early PhaseSeveral ideas and innovations in the field of electron

devices had been reported before 1946, although oftenin somewhat different context. The earliest recordedcontributions in the field are the pioneering works ofSir J.e. Bose on microwave detectors2•3• He had alsoinvented a detector using a point contact galenacrystal. Fig.2 is a reproduction of the original USpatent certificate of the latter. A 100 years ago Bosehad been thinking of a device for direct conversion ofsolar light into electricity. We find the followingsignificant entry4 in his diary dated 5th March, 1985:

"I have been long thinking whether the vast solarenergy that is wasted in the tropical region, can in anyway, be utilized. Of course, trees consume the solarenergy. But is there no other way of directly utilizingthe radiant energy of the sun?

Taking advantage of the heating effects, there have

367

.i

INDIAN J RADIO & SPACE PHYS, VOL. 15, OCTOBER & DECEMBER 1986

BHABHA CX'N.MTI SOLI D 51 ATE PHASE I OOE

CAL.UNIV

SV.UNIVSSPLTIFR

lIT's

KAL.UNIVCEERIBARG

lISC

KUllJ.UNIVNPLISPD

B.H.UNIV

PUN.UNIVNCLBEL

J AD.UNI V

BITSlACSECIL

aJR.UNIV

DEL.UNIVCELBHEL

IN! .PHASE

CAL.UNIV

lIT KHARAGPUR

B.H.UNI V

NPL

VAC DEVICE PHASE

EARl. Y PHASE

J .C. BOSE 1895, 1904 - (BOSE INST)

DISCHARGE TUBES

OOUNTER TUBES (GAL UNI V)

X-RAY TUBES ( DO )

DEMOUNT ABLE DEVl CES (BOSE INST)

L.F./LOW POWER

GAL UNIV

DEL UNIV

lISc

ALL UNI V

HF/HIGH POWEWMISC

CAL UNI v/nscNPL B.H.UNIV

CEERI TIFR

BEL BARC

ECIL

1895 1915

1

19~j

1975 1980

Fig. 1- Various phases of work on electron devices in India andsome of the active centres thereof

been attempts to construct a solar engine which ismerely a heat engine. We may also get thermoelectriccurrent by heating one of the junctions. But suchthermoelectric batteries are practically of not muchuse. Great amount of energy is also lost by the wastefulconduction. Now I have thinking whether we wouldnot directly convert the energy of light into that ofelectric current. ';

And 20 years later he succeeded in developing adevice that converts light into electricity and went onto have this patented along with his galena crystaldetector referred to earlier5. This was actually the firstdry type photo voltaic cell using a compoundsemiconductor. However, with lapse of time Bose'sinterest had perhaps shifted and his patent actuallydealt with the use of the device for detection and

measurement of intensity of light and not for energyconversion. He called the patented device aTejometer' a Sanskritized name for intensity meter6•7•

He also developed other quite important generatingand guiding devices in course of his monumental workon microwaveH• Prof. Mitra gave an illuminating

368

account of this work in his 1945 Sir J.C. Bose memorial

lecture9. Gaseous discharges formed topics of researchat several places including Professor Mitra'slaboratory1o. Mitra and Sil11 had also done someinteresting work on the transit time loading of a triodeat high frequencies in 1932. The technique offabrication of Geiger counter and Wilson cloudchamber was developed at Prof. Saha's laboratory andthe Bose Institute at Calcutta in the late thirties and

early forties 12.13. Demountable vacuum tubes weresuccessfully designed and constructed for generatinghigh power r.f. ultrasonic waves at more than oneplaces early in the forties.That was also the time whenX-ray tubes were constructed in India. However, thesewere rather casual developments-incidental to workin other fields. There was no attempt at upgrading orstudying them for their own sake.

2.2 The Vacuum Tube Phase

The purpose of the C.S.I.R. project of 1946, referredto earlier, was to remove this lacuna by carrying outdevelopmental work up to the pilot plant stage. It was,

'I'

DEB: EVOLUTION OF RESEARCH ON ELECTRON DEVICES IN INDIA

'UUTEO MU. aI. I¥Ui

J C I:IU81:.

DtTtOTOI 101 tL!:CTll.II:A.r.. OIITOUANCU .•n~lr.'I" flU. un •• ""

Fig. 3- Some earliest electron tubes fabricated in India

emission carried out by Prof. K.S. Krishnan atAllahabad with particular reference to the methodevolved by him on measurement of thermionicconstants using thermal effusion .

In view of the challenges put forward by thetransistor in the field of low power devices, interest atCalcutta started shifting towards high power devicesand a project was framed on X-band TW magnetron.Fig.4 illustrates a section of the laboratory built up forthe purpose with the details of the magnetrondeveloped shown in the inset. Almost simultaneously,with this, the National Physical Laboratory, NewDelhi, started work in the same field with Dr AmarjitSingh as the project leaderl9. Fig.5 shows thecomponents and other details of the magnetroninvestigated by him. The activities shifted to theCEERI, Pilani, when Singh left for the place. At Pilanihe built up the vacuum tube laboratory quite quicklyand did, among other things, valuable work on thedevelopment of an Inverted Interdigital Magnetron.Of the other devices investigated here, coaxial-typepower tube20, xenon flash lamp, TV pick-up tube, highpower crossed-held devices and guns deservemention21. Meanwhile, the National PhysicalLaboratory, in the late fifties, launched a project on thedesign and fabrication of reflex klystron and car~ied itto the batch production stage. At a much later stage, in1975, the Electronic Engineering Department of theBHU started a project on high power klystron andTWT22. The NPL also developed know-how on CRTand TV picture tubes. None of the products developed,however, is known to have been commercially

exploited. A highlight that deserves special mentionwas the work on thermionic cathodes and He-Ne laser

at the IISc, Bangalore23 -25.Other organizations which started work on vacuum

tubes during the 60's and the 70's were: The TataInstitute of Fundamental Research (TIFR) - TR­

switches and high power klystrons23.24.26; The

•• Il'VrlI'VfOJt

;", .•. 1... a....t- -L_ ./.(~L. _

~\;).~,_ .. {<)U'r~_ (~ .•

•••.·' ••••'.\/1

~.•• ,'.V,..,i;"'J ..'~~,..V'

1:':0 3

@- 1 I~

" ~.. ,~ :~~

" W j;;,

Fig. 2- Sir J C Bose's US Patent document for microwave detectorusing point contact galena

of course, restricted in scope, to receiving tubes only.Fig.3 illustrates some of the earliest tubes developedunder the project14. Laudable though, the projectturned out to have been rather ill-timed because of

three new developments, viz. (i) within a few months of

its launching, life in Calcutta came to almost a grindinghalt because of prolonged communal trouble, (ii) justafter a year or so, in August 1947, India becameindependent, and in view of the pressing needs ofdefence services, the Government of India decided togo in for foreign. collaboration for production ofelectron devices rather than adopting the more time­consuming course of development of indigenousknow-how, and (iii) in another year the BellTelephone Laboratories announced the invention ofthe transistor. Nevertheless, the effort continued for

sometime not only at Calcutta 14but also ~ubsequentlyat Delhi University and later on at the Indian Instituteof Science, Bangalore - both on receiving tubes. Thetransistor had a fairly long teething trouble. This, andthe momentum already generated, however, helped to

carryon the work on vacuum tubes for several yearsmore. Some of the contributions during this periodincluded transit time effects in triode by Chatterjee andSreekantan 15from the IISc, Bangalore, oxide cathode

poisoning, theory and design and operation of severalspecial types of gridded valves from the CalcuttaUniversityl6 -18. A notable contribution during thisphase was perhaps the investigation on thermionic

369

INDIAN J RADIO & SPACE PHYS, VOL. 15, OCTOBER & DECEMBER 1986

Fig. 4- A part of the laboratory at Calcutta for work on highpower microwave magnetron and parts of the first magnetron

assembled (inset)

Bhabha Atomic Research Centre (BARC)- imageconverters, image intensifiers and phototubes23,24;The Bharat Electronics Ltd (BEL) - transmitting,microwave and display tubes23,24; The ElectronicsCorporation of India (ECIL) - microwave anddisplay tubes23,24.

The above account, of course, confines to thosedevices which are of interest to Electronics and

Communication. On. a broader perspective, anelectron microscope, a cyclotron and an MHDgenerator may be classed as special types of electrondevices, Work had been carried out on development ofthe first two at the Saha Institute27, Calcutta, and thelast at the TlFR, Bombay,

2.3 The Interim Phase

Although 1948-49 saw the birth of the transistor, ittook about 5 years more to have it established as acommercial proposition. This and the entirely differentbasic physics of its operation and the lack ofavailability of the relevant materials and devices in thelocal market.constituted serious hurdles in undertak­ing any work with it in India. On the other hand, therewere reasons to believe that it would

eventually replace at least the receiving types of tubesand as such no new projects on investigation on thelatter were undertaken during the period. Instead, and

quite rightly, interest shifted to microwave and highpower devices as already mentioned, However, somepreparatory work was done to initiate researches onsemicondu::tor devices. Transistor started appearingin the local market around 1953-54. Exploratorystudies on its operation and investigations ontheoretical aspects were also started, in a small way, ina few laboratories. As far as the present author is awareof, the first publication on transistors in India toappear was one on studies on transistors connected inparallel by A,N, Daw28 of the Calcutta University in1955, Some theoretical works on transient response oftransistors29, on determination of their physical andgeometrical parameters 30 and noise3!, formed othercontributions from the same place, The other centresto start work in the field during this period were thelIT, Kharagpur32 -35, the Banaras Hindu Uni­versity36,37, Kalyani University38,39and the NationalPhysical Laboratory. Work on Bose's historical pointcontact devices was also revived during this period atthe Bose Institute40, By the end of the 50's the wideranging possibilities of the transistor in respect of gain,frequency and power had not only been clearlyestablished but the advent of other new types of deviceslike the solar cell, the varactor, and the t~nnel diodeshad laid firm foundation of the semiconductor familyof electron devices. There was 'Iittle doubt that forfruitful results in the field, ad hoc approaches andcasual studies would be of little help, A brief survey ofactivities during the interim phase has been given byAchuthan4! ,

2.4 The Semiconductor Phase: General Features

The clear indication that semiconductor devices had

come to stay helped to initiate work on them on a moreplanned and systematic fashion at several places in theearly 60's. The most notable of these was, of course, thesetting up of the Def~nce Solid State PhysicsLaboratory. The Solid State Division of the NationalPhysical Laboratory, the semiconductor wings of theCentral Electronics Engineering Research Instituteand the Tata Institute of Fundamental Research alsostarted taking shape during this peiod23,24. Efforts inthe same direction started in several educational

Fig. 5- The part of the microwave magnetron fabricated at the NPL

370

_._---------,-----------------

DEB: EVOLUTION OF RESEARCH ON ELECTRON DEVICES IN INDIA

Table 1-Estimatesof Componentsand SpecialMaterialsRequired by the Country for Production of Electronic

Goods by 1965 and 1970

Institutions including Calcutta University, liT Kanpur,IISc Bangalore and Jadavpur University. The well­known report of the Bhabha Committee onElectronics appeared during this decade. The crucialrole of basic materials and components was adequatelystressed in the report as can be seen from the estimatedfigures for 1965 and 1970 given in Table 1.

Although the need for adequate investment in R&Don electronic materials and devices is implicit enoughin these figures, the absence of any explicit directive inthis regard seems to have served as a handicap in lateryears. And the trend persisted even when theElectronics Commission started to function at aboutthe end of the sixties. This was a really unfortunatestate of affairs that almost swept us off our feet when,in the next decade, viz, 1970-79, the age of integratedcircuits, mini- and microcomputers, MICs andOptoelectronics stormed into the world and the spectreof the energy crisis gave a tremendous boost to theresearches on direct energy conversion devices like thesolar cell. Some corrective steps were hurriedlyiaitiated. The Electronics Commission set up a specialCommittee on Semiconductor. Valuable documents

were prepared dealing with the Rand D inComponents and Materials and manpower training inelectronics23.24.But by then the craze for the so-called'screw driver technology' had gathered such amomentum that the required follow-up actions almostwent by default. Confusion and dithering com­pounded as high-tech products of this craze, marked'Made in India' started appearing in the market, while,in reality, the electronic boom was steadily slipping outof our hands. As the age of the microprocessorestablished itself firmly and that of the VLSI appearedto be distinctly dawning, a move was taken once againto retrieve the lost ground through the setting up of theSemiconductor Complex and strengthening of RandD facilities in a number of National Institutes like theCEERI, TlFR, ISRO, NPL and the creation ofreasonably good teaching and research laboratories onSemiconductor Devices including ICs at the IITs andthe IISc. A National task force on microelectronicswas also constituted in 1982-83 to draw up acomprehensive plan of action enabling the country to

Year

1965

1970

Total productionof electronic

goods (in crores

of Rs)

37.5

135.0

Value of components

required

(in crores of Rs)

6.5

40.0

Value of specialmaterials

required (in

crores of Rs)

1:0

7.5

leap into the VLSI age. The recommendations of thebody are about 2 years old now. It is reported that anaction plan, involving an investment of about Rs.500crore, aimed at self-reliance in microelectronics, hasbeen adopted by the Government on the basis of these.But the ball of implementation has not yet startedrolling. There are reasons to fear that this might witherunder the heat of the latest Government enthusiasm

for imported know-how.

3 Contribution of a Few Rand D Units onSemiconductor Devices

Comprehensive and planned programmes of workof semiconductor research have been, largely, lackingin India. Nevertheless, the sum total of thecontributions has been quite substantial. The period1955-65saw, largely, the activities confined to discretedevices. New areas explored during this periodincluded laser, infrared and submillimeter wavedevices. The period 1968-70 saw some"activities in thefield of solar cell with Jadavpur University in theforefront42. But during the next 10 years there wastremendous surge in this area at other places to043.44.From 1975 onwards, expansion in activities was seenon microelectronics with the lIT Delhi, the TlFR andthe Semiconductor Complex dominating the scene. Inthe following, some representative organisation-wisebreak-up of activities is given. It should be stressed thatthis should, by no means, be regarded ascomplete23.24.42--45.

(i) lndustries- The BEL, the ECIL, and the CELdeveloped a number of devices. The BEL developeddiodes, transistors, varactor diodes and TTLintegrated logic circuits- maintaining close col­labonHion with the TlFR and the SSPL. The ECIL,maintaining similar relationship with the BARC,developed know-how for Zener diodes, powertransistors, thermoelectric cooling elements andradiation detectors. The CEL developed technologyfor fabrication of LED and large area single crystal Sisolar cells of commercial grade using imported chips. Italso worked for some time on polycrystalline Si cellsusing the processes developed at the NPL. The BHELat Bangalore carried out work for development oftechnology for making power transistors and Si-singlecrystal solar cells of up to 4 in in diameter.

(ii) NationalLaboratories- The SSPL, set up in1962,worked on a variety of items, e.g. Si point contactdiodes, Si varactor diodes, Si planar power transistors,epitaxial VHF transistors and solar cells. In this lastfield its contributions to the physics, design andmeasurement, chiefly by Jain and his associates, havebeen very substantial46 -50. Some linear ICs have alsobeen successfully developed here. Lately its interest hasshifted to TED, LSI and VLSI45. The chief strength of

371

INDIAN J RADIO & SPACE PHYS, VOL. 15, OCTOBER & DECEMBER 1986

SSPL lies in the comprehensive facilities it has forstudies of materials.

The CEERI at Pilani worked on the development ofTO-IS and TO ..5 headers, Si planar transistors, high­

power high-frequency transistors, LED, Varactordiodes, thin film devices, Si logic gates including 4­

input TTL-NAND and RTL-NOR and 2-input TTL­NAND gates, computer aided circuit design facilities,solar cells using concentrated radiation and hotelectron devices -the last item in collaboration with the

Institute of Radio Physics and Electronics, CalcuttaUniversity. Recently it is also engaged in developingequipment for electron beam lithographl5.51 53.

The TIFR worked on Si planar devices, pointcontact diodes, Gunn diodes, medium and high powerSi controlled rectifiers, digital ICs includingVLSI/CAD, thin film hybrid circuits, C(-SiHdevices23.24.54.

The BARC worked on a large number of devicesincluding special types of devices like pulsed andRaman lasers and Gunn diodes24.55 --58.

The NPL had worked on thin film and rectifier type

devices59 -61. It developed considerable facilities formaking polycrystalline Si and thin film Cu2S-CdSsolar cells44. Of late, it has also developed substantialfacilities for growing and studying of amorphous Si(Ref.59). A somewhat related achievement was thedevelopment of know-how for xerography.

The NCL had, early in the sixties, done some workon design of solar cells.

The Vikram Sarabhai Space Centre at Trivandrumhad for some time worked on development of thin filmCU2S-CdS solar cells43.

The National Remote Sensing Agency and theISRO are doing some work on IR and remote sensingdevices.

The Indian Association for the Cultivation of

Science, Calcutta has been working on development of(J(-SiH solar cells for the last few years44.

The Saha Institute of Nuclear Physics had also donesome work on semiconductor radiation detectors.

(iii) Academic institutions- In respect or facilities,the IISc in Bangalore and the IITs have been in theforefront in the field among the academic institutions.Among others, universities of Calcutta. Jadavpur.Delhi, K urukshetra, Kalyani, the Birla Institute of

Technology and Science at Pilani and others deservemention.

The Departments of Physics, Electrical Engineeringand High Voltage Engineering at the JlSe. Bangalorehaw carried out lIlwstlgations on Si power rectifiers.pyroelectric infrared detectors. Hall cfket devices.JFET. surface wave and amorphous semiconductordevices2J·24.

Departments of Physics and Electrical Engineering

372

and the Centre for Advanced Researches in

Electronics at the lIT, Delhi worked on semiconductordevices. Considerable work has been done on tunnel

diodes, MOS planar transistors, CCD, SAW, p-n

junction photodevices and amorphous semiconductordevices, thin film ICs etc.62 -71 Of late, facilities have

been created for design and fabrication of the SSI andLSI devices and thin film CU2S··CdS and amorphous Sisolar cells 72 -77.

The lIT Kanpur has set up an IC laboratory.Considerable work has also been done on solar

cells43.78, the MOS and the Schottky-barrier devices.The Electronics Department of the lIT, Kharagpur

has built up very good facilities in the area including

computer-aided mask making. Besides, it worked onMICs and thick ..film solar cells. The Material Science

Centre here has done work on semiconductor/elec­

trolyte solar cells43.44. 79. Its effort in developingtechnique for Si growth out of rice husk incollaboration with the Physics Department, deservesmention. The lIT, Madras has facilities for making p-i­n diode and MOSICs80.81. It has also worked on

thyristors, polycrystalline GaAs solar cells anddiffused junction solar cells51. The Bombay lIT hasdone work on thin films, MICs, hybrid devices andsolar cells.

As already mentioned the Institute of Radio Physicsand Electronics of the Calcutta University has been thepioneer in the field of researches on semiconductordevices. Unfortunately, the lopsided and faultynational policy of excluding the universities from themain stream of research efforts, did not allow it to

receive the support it deserved. Nevertheless, itscontributions to the understanding and operation ofthe transistors, the Gunn diodes,hot- electron physics,the IMPA TTs, the UJT junction ..type lasers, Schottky ..barrier diodes and the solar cells have been quitesubstantial over the years82 -93. It is encouraging tonote that, very recently, it has received adequate fundsfor strengthening facilities for crystal growth, andfabrication of microwave and microelectronic devices.

At the Banaras Hindu University its Physics and theElectronic Engineering Deparements have been quiteactive in semiconductor device researches. The main

item of investigation has been the solar cell. Recently,the laboratory has been modernized and work on theIMPA TT and Opto .. and microelectronic devices hasbeen initiated43.44.94 98.

Jadavpur University had done work on gas lasers,infrared and sub-mm wave detectors and modulators

in the sixties (Fig.6). It had been the pioneer in India inresearches on solar cells with emphasis both on thephysics and on the design and fabrication of thin filmsolar cells3H.'i'i 113 and development of X..rayxerography 114.115.

t

., '1'

DEB: EVOLUTION OF RESEARCH ON ELECTRON DEVICES IN INDIA

Fig. 6- A part of thc Laser Laboratory at Calcutta University

The Poona University started systematic work on 0'.­

SiH solar cells a couple of years back.Among other works worth mentioning are on FET

bipolar junctions at the Gorakhpur Universityl16-118,works on solar cells at Delhi University49,So,119, on IRdetectors at the SV University, TirupatiS1, on CdSesolar cells at Indore UniversitySl, on GaAs solar cells atthe Regional Engineering College, Srinagar51, onVLSI simulation at Madras University44, on MISsolar cells at the DRS College, Dehradun and on solarcell physics at the Kalyani University120 -123, theBITS, Pilani 124.125 and the Governmen t College,Ajmer43.

4 Concluding RemarksIt would appear from the above that the volume of

activities on electron devices in India has certainlygrown considerably over the years. But a coherentevolution in the field has not taken place. This has beencaused, largely, by the absence of a clear-cut NationalPolicy on this matter. The setting up of theSemiconductor Complex and the formation of thenational task force on microelectronics and its

comprehensive recommendations aimed at catchingup with the age of the VLSI had given much room forhope. The move for creation of national Si facilities,and of a National Microelectronics Council, and the

start of a policy of providing liberal support forbuilding Lip research centres at the academicinstitutions, are also healthy signs in this respect. Butas yet the primary need of a research-conscious,innovation-minded and forward-looking electronicsindustry and its continuous interaction with theNational Laboratories and academic research centres,

remains a distant goal. All efforts would prove to befutile unless this is realized. And for this a firm policyof basic self-reliance in electronics industry must beclearly announced and vigorously pursued. It is all themore necessary in view of the latest policy ofItberalization of import of know-hows. This latter

must not be adopted. as an ad hoc mcasure. to achievea short-term. apparently rosy goal. Rather, a plan ofactlonlllust be carefully chalked out for assimilation of

these as a means of toning up a natural growth ofindigenous effort ensuring a true evolution of ourresearches in the field of electronic materials anddevices.

References

1 Mitra S K & Bhar 1 N, Sci & Cult, 1 (1936) 755.

2 Bose 1 C, Proc R Sac London. 65 (1899) 166.3 Bose 1 C, Proc R Sac London, 66 (1900) 45,452.

4 Chatterjee S D, Private communication to the author, 1976.

5 Bose 1 C, U SPat No.755840, 1904.

6 Lange B, Photoelements and their applications (Reinhold, New

York). 1938. 39.7 MOS5 T S, Proc IRE London. 43 (1955) 1864.

8 Bose J C, Collected Physical papers (Longmans Green & Co.,London), 1929.

9 a) Mitra S K, Microwaves - Pioneer Work in India Half a

Century Ago, J l. Bose Memorial Lecture, November 30,1946.

b) Ramsay F F, Proc IRE London, 43 (1955) 405.c) Pearson G L & Brattain W H, Proc IRE London, 43 (1955)

1974.

10 Mitra S K & Syam P, Phil Mag, 8713 (1932) 86.

11 Mitra S K & Sil B C, Phil Mag, 8714 (1932) 92.12 Dasgupta N N, Trans Natllnst Sci India, 2 (1942) 121.

13 Dasgupta N N & Ghosh S K. Rev Mod Phys, 18 (1946) 225.

14 Deb S & Sen S K, J Sci Ind Res, 8 (1949) 312.15 Chatterjee S K & Sreekantan B K, Indian J Phys, 23(1944) 119.

16 Deb S, J Sci Ind Res, 88(1949) 214: 108(1951) 77: Indian J Phys,25 (J 952) 377: J Br Instn Radio Engrs, 14 (1954) 157.

17. Deb S & Sanya1 G S, J Appl Phys, 28 (1954) 1946.

18 Deb S, Proc lEE, New York, 1029 (E 55) (1955) 469.

i 9 Singh Amarjit et al., J Sci Ind Res, 16A (1957) 169; ProcIREJ.,USA), 43 (1955) 470; In! J Electron Control (USA), 3(1957) 183; Proc Inst Elect Eng(GB), 1088(1961) 550; 1098

(1962) 145; J Inst Telecommun Eng (India), 6 (1960) 153.

20 Sidhu G S, Singh D & Singh A, J Instn Engrs India, 14 (1968)458.

21 Wadhwa R P & Mishra V K, Trans IEEE, ED-16 (1969) 977.

22 Vaidya N C, Prac IEEE, 60 (1972) 248; Optik (Germany), 42(1975) 129.

23 Electronics Information and Planning (The ElectronicsCommission IPAG), 1(1973) 257 & 286.

24 Ref. 23 except I (1974) 922 & 931.

25 Sat yam M. J Insln Telecommun Engrs, India, 13 (1967) 492.

26 Proceedings of the Symposium on Electronics (Microwave

Technology), BARC, Bombay, Feb 25-27, 1970.

27 Dasgupta N N, De M L. Bhattacharya D L & Choudhury A K.Indian J Ph)'s, 22 (1946) 497.

28 Daw A N, Indian J Phys, 29 (1955) 121.

29 Bhattacharya 1 C, J Instn Telecommun Engrs India, 3(1957) 297.30 Deb S & Daw A N, Int J "Electron Control, 5 (1958) 514.31 Dcb S & Daw A N, J Br Insln Radio Engrs, 21 (1961) 49.

32 Achuthan N K, Electron Radio Eng, (1957) 309.

33 Bose K K, Electr Eng, 30 (1956) 439.34 Achuthan M K. Electr Technol, 31 (1960) 230.

35 Achuthan M K. EleClr Technol, 38 (1961) 458.

36 a) Bhattacharya A B & Chattopadhyay S K, J I C C(India), 43,ETi (1962).

b) J Sci Ind Res, 21A (1962) 162.

37 Bhattacharya A B, SOl'iet Radio En!?, 36 (1966).

38 Dutta Roy S C, lilt J Electron Control. 14 (1963) 445.

39 Dulla Roy S C. Int J Electron CO/1/rol, 18 (1965) 99.40 Achulhan M K, J Illstll Enws(lndia). PI ET, 65(1985) 103.

373

INDIAN J RADIO & SPACE PHYS, VOL. 15, OCTOBER & DECEMBER 1986

41 ChatterjeeS D& SenS K, Trans Bose Res Inst, India, 20(1955)161.

42 Deb S & Mukherjee M K, Int J Electron, 21 (1966) 89.43 Proc Natl Solar Energy Soc India, SESI, Calcutta, Nov 29-Dec

2,1976, New Delhi, December 17-19,1982.44 Photovoltaic Materials and Devices, edited by B K Das & S N

Singh (Wiley Eastern, New Delhi) 1985.45 Proc Int Workshops on the Physics of Semiconductors, edited by

S C Jain et al., Nov 23-28, 1981 and Dec 5-10, 1983.46 Jain S C, Seghal H F & Gangadhar R B, J So' Ind Res, 27 (1968)

295.

47 Sreedhar A K, Sharma B L & Purobit R K, Trans IEEE, ED 16(1969) 309.

48 Jain V K & JainS C, Phys Status Solidi, (a) 3 (1975) K 68.49 Dhariwal S R, Kothari L S & Jain S C, J Phys D: Appl Phys, 8

(1975) 1321.50 Dhariwal S R, Kothari L S & Jain S C, Trans IEEE, ED-23

(1976) 504.51 Gopalan B S V (Ed), Proc International Conference on the

Physics and Technology of Compensated Semiconductors(Abstracts), llT, Madras, Feb 20-22, 1985.

52 Singh J & Marathe B R, J Instn Telecommun Engrs, India, 12(1966) 621.

53 Sahasrabuddhe C G & Khokle W S, Int J Electron, 24 (1968)177.

54 Bhattacharya T K, Electron Leu,S (1969) 408.55 Dastidar P R, Ravindran K & Pant H C, Electron Leu, 5 (1969)

553.

56 Dastidar P R, Indian J Pure & Appl Phys, 8 (1970) 491.57 Bhawalkar D D, Proc Indian Natl So' Acad, 37 (1971) 200.58' Jha S S, Proc Indian Natl Sci Acad, 37 (1971) 219.

59 Josh M V, Indian J Pure & Appl Phys, 7 (1969) 607.60 Mehta S C & Prasad R, Indian J Pure Appl Phys, 7 (1969) 621.61 Mehta S C & Prasad R, J Appl Phys, 41 (1970) 760.62 Sarnot S L. & Bhattacharya A B, Int J Electron,S (1969) 275.

63 Gangadhar R B & Bhattacharya A B, Solid State Electron, 12(1969) 887.

64 Bhattacharya A B, Gupta M L & Gard V K, Microelectronics &Reliability, 9 (1970) 347.

65 Bhattacharya A B & Gupta M L, Solid State Electron, 16(1973)1506.

66 Kumar R & Bhattacharya A B, Trans IEEE, ED-24(1977) 1270.

67 Sudhar P, Bhattacharya A B & Mathur B, lEE J Micro Opticsand Acoustics, 2 (1978) 65.

68 Bhattachar)la A B & Wallinga H, Trans IEEE, ED-29 (1982)827.

69 Lakshmi E & Bhattacharya A B, Solid State Electron, 25 (1982)811.

70 Bhattacharya A B, Proc IEEE, 71 (1983) 144.

71 Visweswaran G S, Jain N K & Bhattacharya A B, ElectronicLett, 21 (1985) 331.

72 Gangadhar R B & Bhattacharya A B, Int J Electron. 25 (1968)17.

73 Das S R. Nath P, Banerjee A & Chopra K L, Solid StateElectron, 21 (1977) 49.

74 Das S R, Vankar V D. Nath P & Chopra K L. Thin Solid FilII/.\'.51 (1978) 257.

75 Banerjee A, Das S R. Thakoor A P. Randhawa H S & Chopra KL. Solid Statc Electron, 22 (1979) 495 & 533.

76 Saxena S. Pandya D K & Chopra K L. Thin Solid FilII/.\'.94(1982) 223.

374

77 Purushottam M, Das S R, Mukherjee A K & Chopra K L, ReI'

Sci Instrum, 55 (1982) 1749.

78 Bhowmik B & Sharan R, App Phys Leu, 29 (1976) 257.79 Bose D N, Ramprakash Y & Basu S, J Electrochem Soc, 131

(1984) 850.80 Bhat K N & Achuthan M K, Trans IEEE, ED-24 (1977) 205.81 Achuthan M K & Vitto T J, Int J Electron, 33 (1972) 573.82 Daw A N & Mitra R K, lnt J Electron, 27 (1969) 97.83 Nag B R & Guha S, Br J Appl Phys, 16 (1965) 1461.84 Chakrabarti A N, J Sci lnd Res, 24 (1965) 452.85 Chakrabarti A N, J Appl Phys, 37 (1966) 446.86 Daw A N, Mitra R N & Choudhury N K D, Solid State

Electron, 10 (1967) 359.87 Choudhury N K D & Daw A N, Int J Electron, 23(1967) 183.88 Chakrabarti A N, Int J Electron, 22 (1967) 307, 355.

89 Roy S K & Pal B B, J Phys D, Appl Phys, 4 (1971) 2041.90 Roy SK, Som B & Pal B B, Proc IEEE, 63 (1975) 1072.91 Roy S K, Ghosh R& Pal B B, Proc NASECODE IConfDuhlin,

June 29, 1979, 266.92 Roy S K. Appl Phys, 35 (1984) 125.93 Roy S K, Proc NASECODEIV Conf, Dublin, June 17-19, 1985.94 Srivastava R S, Int J Electron, 32 (1972) 347.95 Singh B R, Rai S S & Srivastava R S, Phys Status Solidi, 13

(1972) K 49.96 Swami R& Tantry B A P,lndianJ Pure Appl Phys, 7(1969)556.97 Srivastava S K & Sinha A P B, Solid State Electron, 13(1970) 57.

98 Gupta R S, Int J Electron, 26 (1969) 533.99 Deb S & Choudhury P K, Proc IEEE, 53 (1965) 81.

100 Deb S, J Sci Ind Res, 24 (1965) 398.101 Deb S & Mukherjee M K, Trans IEEE, QE-l (1965) 219.102 Deb S, J/nstnTelecommun Engrs, India, 11 (1965) 412.103 Deb S & Choudhury P K, Solid State Electron, 9 (1966) 113:&

10 (1967) 288.104 Deb S, Mukherjee M K & Basu A K, Br J Appl Phys, 1 (1968)

1133.

105 Deb S & Mukherjee M K. Infrared Phys, 11 (1970) 195.106 Deb S & Choudhury P K, Electron Lett, 3 (1966) 267.107 Deb S & Saha H, Solid State Electron, 15 (1972) 1389.108 Deb S & Saha H, Solar Energy, 17 (1975) 67.109 Deb S, Mukherjee M K & Saha H, Solar Energy. 19(1977) 171.110 Deb S & Maitra K, Solar Cel/s, 9 (1982) 215.111 Deb S & Ghosh B, Solar Cel/s, 13 (1984) 145.112 Mukherjee M K & Das S N, Trans IEEE, ED-21 (1974) 379.113 Mukherjee M K, Das S N & Saha A R, Solid State Electron, 18

(1975) 716.114 Mukherjee M K, et 01., IEEE Trans. IA-19 (1983) 652.

115 Mukherjee M K, et al., IEEE Trans. IA-21 (1985) 535.116 Misra M & P~asad H C, Proc IEEE, 60 (1972) 227.

117 Misra M & Prasad H C, Solid State EI('~tron. 15 (1972) 325.118 Prasad H C & Gupta R N. Solid State Electron. 15 (1972) 467.

119 Srivastava G P. Mathur P C, Tripathi K N & Lomash S K. PhysLett. 28a (1972) 487.

120 Basu P & Saha H. Solid State Electron, 20 (1977) 553.

121 Saha H. Basu P. Mukhopadhyay K & Sengupta S.lndian J PureAppl Phys. 17 (1979) 515.

122 Saha H, Mukhopadhyay K & Biswas D, Int J Electron,49(1980)313.

123 Mukhopadhya~ K & Saha H. Solar Cel/s. 4 (1981) 135.124 Tewary V K, Kothari L S & Jain S C. Solar Cel/s, 20( 1977)297.125 Agarwal A, Tewary V K, Agarwal S K & Jain S C. Solid State

Electron, 23 (1980) 1021.

, I r-I 1'·1 fllilil t"1 11 , II"