1. 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

2. Metal-Oxide-Polymer Sensors and Devices
Point of Contact: Robert Dahlgren, robert.p.dahlgren@nasa.gov (650) 810-0229
Description/Goals/Objectives/Issues/TRL Concept Image/Customers/Team
Concept Description: Concept Image:
- Metal Oxide Polymer Sensors and Devices
Goals & Objectives:
- Model the device behavior and application space
Issues: Customers:
- New technology and physics - Aerospace and industrial users
TRL: 1 Team:
- V. Vanderbilt (SGE), R. Dahlgren, N. Kobayashi
Technical
Approach/Significance/Application
Technical Approach:
-
Significance:
-
Application:
-
Benefit/Outcome:
-

3. Description, Goals, and Objectives
• Concept Description Applied force
– Serendipitous discovery during rock testing
– Voltage output a function of applied force F
– Metal-Oxide Polymer sensors and devices
+
– Native or engineered oxide barrier
• Goals and Objectives
V –
Metal
Metal
– 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 Polyethylene
(HDPE)
• Issues
– New physics beyond simple capacitive sensor
– Role of oxide quantum mechanical barrier Optional oxide
layers not shown
• TRL
– TRL1 3

4. Concept, Customers, and Team
F
• Concept Image
– Stack of 1018 Steel plates Metal
– Thin (~250 um) high density HDPE –
polyethylene film Metal
HDPE –
– Double layers ~ 40 cm2 each Metal
• Customer
– Users of discrete sensors
– Users of distributed sensors
– Users of conformable force sensor e.g.
sensing of micrometeoroid impact
• Team 60 Ton
– Vern Vanderbilt, Ph.D. Press
(N244)
– Robert Dahlgren, Ph.D.
– Nobuhiko Kobayashi, Ph.D.
4

5. 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

6. 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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