Integrated Smart Nanosensors for Space Biotechnology Applications

1
Integrated Smart Nanosensors for Space
Biotechnology Applications

• Toshikazu Nishida
• Mark E. Law
• University of Florida
• NASA Research Briefing
• September 25, 2002

2
Introduction

• Overview of the Program
• Test Bed Development
• Miniaturization of Macro Sensors
• Nanosensor Development
• Equipment
• Summary and Conclusions

3
Overview

• Goal Develop Low Mass, Low Power Sensors
• Interdisciplinary Work
• ECE, MSE, Aerospace, Chemical, Civil,
  Environmental Involved
• Miniaturize Macroscopic Sensors
• New Applications for NEMs Devices

4
Technical Outline

• Test Bed Development
• Water Purification Mazyck(Environmental)
• Miniaturization of Macro Sensors
• Cumulative Flow Hatfield(Civil),
  Annable(Environmental)
• Gas Sensor Wachsmann (MSE)
• Nanosensor Development
• Flow Sensor Sheplak(Aero) and Nishida (ECE)
• Wide Band gap Sensors Ren (Chem), Chauhan(Chem),
  Pearton(MSE)
• Membrane Development Jones(MSE), Law(ECE)
• Self-Powered Sensors Nishida(ECE), Sheplak(Aero)

5
Integration of Intelligent Sensors for Water
Recovery

• David W. Mazyck, Environmental Engineering
  Sciences
• Technical Leader for Water Recovery
• NASA ES CSTC
• Objective has been to design a micro-gravity
  compatible reactor that removes or destroys
  organics from recycled water
• Two systems currently under development
• Magnetically Agitated Photocatalytic Reactor
• MAPR sponsored by the ES CSTC
• In-situ Regenerated Activated Carbon
• IRAC to be presented at 2002 ICES

6
Project Description

• MAPR
• Magnetic particles are coated with silica and
  TiO2 to photocatalytically degrade organics
• Magnetic field fluidizes particles to enhance
  mixing and destruction rates
• IRAC
• Capture organics through traditional adsorption
  with TiO2 coated activated carbon
• In-situ regenerate carbon once exhausted with UV
  light

7
Research Description

• Optimize MAPR for the destruction of target
  organics
• Improve IRAC regeneration efficiency
• Integrate sensors to monitor or control flow,
  temperature, and specific organics
• Coupled to Fluidic Sensing, Flow Sensors,
  Cumulative Flow Sensor, Membrane Development

8
System Schematic
NEMs Flow Sensor
Integrated Treatment and Sensing System for Water
Purification in Space (MAPR and IRAC
interchangeable).
9
Cumulative Flux Sensor

• Kirk Hatfield, Civil Engineering
• Mike Annable, Environmental Engineering Sciences
• Objective is to miniaturize working system for
  pollutants

10
Cumulative Contaminant Flux

• Contaminants in the flow, q are intercepted and
  retained on the sensor.
• The mass of contaminant retained, Mc is used to
  quantify cumulative contaminant mass flux, Jc

Porous Flux meter
Dye intercepted in a flux meter
Contaminant Intercepted
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Cumulative Water Flux

• The flow field leaches a resident tracer from
  the sensor
• The mass of tracer remaining, Mr is used to
  calculate cumulative water flux, q over exposure
  period, t

Resident Tracer
Porous Flux meter
12
Gas Sensor

• Eric Wachsmann, Materials Science
• Objective to develop a Miniature Low-Power
  Integrated CO/CO2/H2/H2O/O2 Sensor for Space
  Biotechnology Applications

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Gas Sensor

• Simple potentiometric sensor is not limited to a
  specific size and does not require separate
  reference atmosphere
• We have already demonstrated approach provides
  ppm sensitivity for CO and NO and selectivity for
  NO
• We will determine selectivity for CO
• We will determine scalability toward
  nano-dimensions
• In future phase we will produce miniature
  CO/CO2/O2/H2/H2O sensor

14
MEMS Sensors for Environmental Systems

• Dr. Mark Sheplak (Mechanical and Aerospace
  Engineering)
• Dr. Toshi Nishida (Electrical and Computer
  Engineering)
• Objective
• Instrumentation-grade MEMS sensors for
  environmental systems
• Specifically, MEMS flow sensors for water
  recovery reactors
• in collaboration with David Mazyk in
  Environmental Engineering
• Current Technology
• Macroscopic liquid flow sensors
• Turbine
• Vane
• Piston

• Why MEMS Flow Sensor?
• Smaller weight, size, power
• Reduced pressure drop

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MEMS Sensors for Environmental Systems
Flow

• Floating Element Flow Sensor
• Direct detection of flow from imparted shear
  force on floating element
• Flush mounted in fluidic channel wall for minimal
  pressure drop
• Designable for low or high flow rate by adjusting
  spring force (tethers)
• Detection Method for Displacement of Floating
  Element
• Optical Moirè fringe detected via CCD

Figure 1 - Floating Element Principle
Flow
Bottom
Top
Moirè fringe
Figure 2 - Physical Structure
16
Wide Band Gap Semiconductor Based Sensors

• Fan Ren, Chemical Engineering
• Anuj Chauhan, Chemical Engineering
• Steve Pearton, Materials Science and Engineering
• Objectives
• Fabricate different semiconductor SiC and GaN
  based electronic devices to investigate the
  detection limit
• Lateral electric fields can be used to separate
  charged molecules as they flow through a
  micro/nano fluidic channel.

17
Background

• SiC and GaN based materials are chemically and
  thermally stable and suitable for high
  temperature and harsh environment applications
• Electronic devices from SiC and GaN are highly
  sensitive to several gases including hydrogen,
  carbon mono-oxide and hydrocarbons

18
SiC Schottky Diode Based Gas Sensor
19
Schematic of Microfluidic Device
Detector
Fluid inlet
2 mm
Fluid outlet
2 mm
2 cm
electrodes
The electric field concentrates the charged
molecules near the wall, where they slow down due
to the smaller velocities near the wall. The
molecules with smaller diffusion coefficient,
i.e., the larger molecules concentrate more near
the walls, and thus slow down more. This leads
to separation of molecules of different sizes.
Pulse introduced at time0
1
Pulses at different time
0.8
Concentration
0.6
0.4
0.2
0
0
Axial Position
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Membrane Sensor Development

• Kevin S. Jones, Materials Science Engineering
• Mark E. Law, Electrical and Computer Engineering
• Objective is to develop a single crystal silicon
  membrane for use in pressure and mass sensors -
  offer greater reliability and lower noise

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Membrane Sensor Development
Single Crystal Membrane Development

• Operational Capability
• Single Crystal silicon membranes for use as both
• Integrated Pressure Sensors and
• Integrated Mechanical Resonators
• Improved piezo-transducer formation through the
  use of Ultra-low Energy Ion Implantation and
  Laser Thermal Processing
• Estimated Improvement in Dynamic range of 32 to
  160 dB
• Estimate a 10X reduction in the noise floor over
  bonded and etched back MEMS acoustic sensors
• Significant long term resonator stability
  improvement because of the lack of grain creep

Silicon etching and anneal can lead to membrane
Single Crystal membrane 0.75 µm thick
Cavity
0.27mm2 in area
Proposed Technical Approach Develop the Empty
Space in Silicon (ESS) process utilizing focused
ion beam etching and reactive ion etching to
produce etched holes in single crystal
Si Utilize high temperature annealing in a
reducing ambient to flow the silicon over the
etched features creating single crystal
membranes Develop ultra shallow junction
formation methods using plasma assisted doping on
ESS materials for piezoresistive transducers
formation
22
Self-Powered Monitoring of Life Support Systems

• Principal Investigators
• Dr. Toshi Nishida (Electrical and Computer
  Engineering)
• Dr. Khai Ngo (Electrical and Computer
  Engineering)
• Dr. Mark Sheplak (Mechanical and Aerospace
  Engineering)
• Dr. Lou Cattafesta (Mechanical and Aerospace
  Engineering)
• Dr. Jean Andino (Environmental Engineering
  Sciences)
• Motivation
• Flexible deployment of sensors to monitor health
  of life support systems requires self-powered
  wireless sensors
• Target
• To design a MEMS vibrational energy harvesting
  device that enables a self-powered sensor and
  wireless transmitter for ambient air monitoring
  and revitalization

23
Self-Powered Monitoring of Life Support Systems

• Approach
• Cantilever structure with a compliant structural
  silicon/piezoelectric composite beam and an
  inertial mass at the tip
• Design
• Scaling analysis of output power with geometry,
  force, and material properties
• Adaptive power circuitry to maximize power flow
• Tasks
• Detailed design of the MEMS vibrational
  micro-generator (Nishida, Cattafesta, Sheplak)
• Power scaling for integration with electronics
  (Ngo, Nishida)
• Design for insertion into existing ambient air
  monitoring and revitalization technologies
  (Andino)

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Aligned Wafer-Bonding System

• EVG 620 Double-Sided Lithography System
• /- 0.5 mm front-to-backside wafer alignment and
  lithography for fabrication of nano- and
  micro-systems.
• printing modes such as soft, hard, vacuum
  contact and proximity are possible.
• aligned wafer bond capabilities used for the
  fabrication of stacked layers in nano- and
  micro-systems.
• EVG 501 Aligner Capabilities
• precision wafer to wafer alignment processes for
  silicon-direct, anodic, thermo-compression and
  pressure bonding.

Precision aligned wafer bonder (EVG 620 / EVG
501)
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Connections

• Flow Sensor - Water Purification
• Cumulative Sensors with Membrane MEMs and Water
  Purification
• Potentiometric sensing with wideband gap
  materials
• Self-Power Sensor with Membrane Development
• Self-Power with all sensor technologies

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Major 18 month Objectives

• Optimize Water Purification System with
  Integrated Sensors
• Miniaturize Cumulative Flow and Contaminant
  Sensor
• Miniature Low-Power Integrated CO/CO2/H2/H2O/O2
  Sensor
• Demonstrate MEMs flow sensor in Water
  Purification Systems
• Develop Wideband gap materials for sensing
  applications
• Develop Novel Single Crystal Membrane Technology
  for MEMs
• Demonstrate Self-Powered Sensor

27
Conclusions

• Leveraged work offers more immediate payback
• Seed grants are looking are possible
  revolutionary technologies - long term payoff
• Good cross linking between tasks - we aim for a
  real coordinated activity