Engineering topics
Publications and source records attributed to Hong, W..
Long wavelength Quantum Well Infrared Photodetector (QWIP) cameras developed at the Jet Propulsion Laboratory demonstrate the potential of GaAs/A1xGa1-xAs QWIP technology for highly sensitive, low power, low cost, and highly uniform large format FPA imaging systems.
NASA, commercial, medical, and defense applications such as Earth observation systems, astronomy, weather monitoring, thermal mapping, thermography, missile tracking, and night vision aids, etc. require high performance large format long wavelength infrared (LWIR) detector arrays in the range of 8-16 µm.
Quantum Well Infrared Photodetectors (QWIPs) offer greater flexibility than usual extrinsically doped semiconductor IR detectors because the wavelength of the peak response and cutoff can be continuously tailored by varying layer thickness (well width), barrier composition (barrier height), and carrier density (well doping density).
A broad-band infrared detector, sensitive over a 10 - 16 mu m spectral range, based on GaAs/A1xGa1-xAs quantum wells grown by molecular beam epitaxy, has been demonstrated.
In this paper we discuss the optimization of the detector design, material growth and processing that has culminated in realization of 15 micron cutoff 128 x 128 QWIP focal plane array camera, hand-held and palmize 256 x 256 long-wavelength QWIP cameras and 648 x 480 long-wavelength cameras, holding forth great promise for myriad applications in 6-25 micron wavelength range in science, medicine, defense and industry.
In this paper, we discuss the development of very sensitive long wavelength infrared GaAs/AlxGa1-xAs quantum well infrared photodetectors (QWIPs) based on bound-to-quasibound intersubband transition, fabrication of light coupling schemes for efficient light coupling, and demonstration of several long wavelength infrared cameras based on QWIP focal plane arrays.
We demonstrate that SiO(sub 2) cap annealing in the ultra-thin p-type InGaAs/InP quantum wells can be used to produce large blue shifts of the band edge. A substantial bandgap blue shift, as much a 292.5 meV at 900 degrees C have been measured and the value of the bandgap shift can be controlled by the anneal time.
The performcance of this QWIP camera is reported including indoor and outdoor imaging.
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The performance of this QWIP camera is reported including indoor and outdoor imaging.
It is customary to make infrared (IR) detectors in the long wavelength range by utilizing the interband transition which promotes an electron across the band gap (Eg) from the valence band to the conduction.
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In this paper, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array (FPA) and its performance in quantum efficiency, NE(delta)T, uniformity, and operability.
Quantum Well Infrared Photodetectors do not respond to normal incident light due to the Quantum mechanical selection rules associated with intersubband transitions.
In this paper, we discuss the development of this very sensitive long waelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array (FPA) and its performance in quantum efficiency, NEAT, uniformity, and operability.
A 9 (micro)m 256x256 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NE(gamma)) of 26 mK has been achieved. In this presentation, we discuss the development of this very sensitive long wavelength infrared (LWIR) camera based on a GaAs/AlGaAs QWIP focal plane array, its performance in quantum efficience, NA(gamma), minimum resolvable temperature (MRTD), uniformity, operability, and its applications.
A hand-held quantum well infrared photodetector camera has been demonstrated.