FORCE SENSORS BASED ON QUANTUM

MECHANICAL TUNNELING:

A new family of Metal-Oxide Polymer Devices

Robert Dahlgren

Vern Vanderbilt

Code SGE

ARCTek-3 October 16th, 2012

Description/Goals/Objectives/Issues/TRL

Technical

Approach/Significance/Application

Metal-Oxide-Polymer Sensors and DevicesPoint of Contact: Robert Dahlgren, robert.p.dahlgren@nasa.gov (650) 810-0229

Customers:

- Aerospace and industrial users

Team:

- V. Vanderbilt (SGE), R. Dahlgren, N. Kobayashi

Concept Description:

- Metal Oxide Polymer Sensors and Devices

Goals & Objectives:

- Model the device behavior and application space

Issues:

- New technology and physics

TRL: 1

Concept Image/Customers/Team

Concept Image:

Technical Approach:

-

Significance:

-

Application:

-

Benefit/Outcome:

-

Description, Goals, and Objectives

• Concept Description– Serendipitous discovery during rock testing

– Voltage output a function of applied force

– Metal-Oxide Polymer sensors and devices

– Native or engineered oxide barrier

• Goals and Objectives– Model the physics of the device

– Measure I-V characteristic of Schottky junction

– Model electron transport kinetics

– Explore advantages/disadvantages

– Identify potential applications of sensor

• Issues

– New physics beyond simple capacitive sensor

– Role of oxide quantum mechanical barrier

• TRL

– TRL1 3

FF

Applied force

Polyethylene

(HDPE)

Metal

MetalV +

–

Optional oxide

layers not shown

Concept, Customers, and Team

• Concept Image

– Stack of 1018 Steel plates

– Thin (~250 um) high density

polyethylene film

– Double layers ~ 40 cm2 each

• Customer

– Users of discrete sensors

– Users of distributed sensors

– Users of conformable force sensor e.g.

sensing of micrometeoroid impact

• Team– Vern Vanderbilt, Ph.D.

– Robert Dahlgren, Ph.D.

– Nobuhiko Kobayashi, Ph.D.

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Metal

Metal

Metal

HDPE –

HDPE –

F

60 Ton

Press

(N244)

Technical Approach, Significance, and Application

• Technical Approach– Measure 2-terminal I-V Curves

– Measure force-dependent (3-terminal) I-V Curves

– Develop mathematical model

– Evaluate feasibility of sensor (SNR, error budget, linearity...)

– Evaluate feasibility of tunnel barrier devices

• Significance– Scale factor independent of many factors

– First report of oxide-barrier modification of force signal

– Self-powered (or ultra-low power) sensor

– No probe signal needed

• Applications– Force, pressure, weight sensors

– Pressure tanks and vessels

– Smart structures and skins

5

Milestones, Products, Resources

• Benefits / Outcome

– Lead to a new family of sensors, transducers, and electronic devices.

– Won’t be GHz due to low density and mobility of electrons in HDPE.

• Milestones Date after award

– M1: First-order differential equations +4 weeks

– M2: Transit time, mobility effects +8 weeks

– M3: Effect of native oxide tunnel barrier +12 weeks

• Products

– Load cell, pressure sensor, force sensor

• Resources

– Electrometer and data acquisition

– 0.25 FTE for 6 months (Vanderbilt)

– 0.25 FTE for 3 months (Dahlgren) via SJSURF or SETI

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