48 Result(s)
within
P. S. Wijewarnasuriya
-
Article
Monte Carlo Modeling of VLWIR HgCdTe Interdigitated Pixel Response
Increasing very long-wave infrared (VLWIR, λ c ≈ 15 μm) pixel operability was approached by subdividing each pixel into four interdigitated subpixels. High response is maintained across th...
-
Article
Arsenic Diffusion Study in HgCdTe for Low p-Type Do** in Auger-Suppressed Photodiodes
Controllable p-type do** at low concentrations is desired for multilayer HgCdTe samples in a P +/π/N + structure due to the promise of suppressing Auger processes...
-
Article
Dislocation Reduction of HgCdTe/Si Through Ex Situ Annealing
Current growth methods of HgCdTe/Cd(Se)Te/Si by molecular-beam epitaxy (MBE) result in a dislocation density of mid 106 cm−2 to low 107 cm−2. Although the exact mechanism is unknown, it is well accepted that this...
-
Article
Ex Situ Thermal Cycle Annealing of Molecular Beam Epitaxy Grown HgCdTe/Si Layers
We present the results of ex situ thermal cycle annealing (TCA) of molecular beam epitaxy grown mercury cadmium telluride (HgCdTe) on Cd(Se)Te/Si(211) composite substrates. We examined the variation in the etch p...
-
Article
Topography and Dislocations in (112)B HgCdTe/CdTe/Si
Scanning electron microscopy (SEM), atomic force microscopy (AFM), and x-ray diffraction (XRD) measurements all indicate an approximate factor of ten increase in the Everson etch pit density (EPD) over standar...
-
Article
Modeling of LWIR HgCdTe Auger-Suppressed Infrared Photodiodes under Nonequilibrium Operation
The general approach and effects of nonequilibrium operation of Auger-suppressed HgCdTe infrared photodiodes are well understood. However, the complex relationships of carrier generation and dependencies on no...
-
Article
Surface Morphology and Defect Formation Mechanisms for HgCdTe (211)B Grown by Molecular Beam Epitaxy
The surface morphology and crystallinity of HgCdTe films grown by molecular beam epitaxy (MBE) on both CdZnTe and CdTe/Si (211)B substrates were characterized using atomic force microscopy (AFM), as well as sc...
-
Article
Passivation effect on optical and electrical properties of molecular beam epitaxy-grown HgCdTe/CdTe/Si layers
The effects of passivation with two different passivants, ZnS and CdTe, and two different passivation techniques, physical vapor deposition (PVD) and molecular beam epitaxy (MBE), were quantified in terms of t...
-
Article
Correlation between visual defects and increased dark current in large-area Hg1−xCdxTe photodiodes
The Cross-Track Infrared Sounder (CrIS) program [an instrument on the National Polar-Orbiting Operational Environmental Satellite System (NPOESS)] requires photodiodes with spectral cutoffs denoted by short-wa...
-
Article
Correlation of CdZnTe(211)B substrate surface morphology and HgCdTe(211)B epilayer defects
We present results on the surface morphology and recombination lifetimes of molecular-beam epitaxy (MBE)-grown HgCdTe (211)B epilayers and correlate them with the roughness of the CdZnTe substrate surfaces. Th...
-
Article
1/f noise in large-area Hg1−xCdxTe photodiodes
The 1/f noise in photovoltaic (PV) molecular-beam epitaxy (MBE)-grown Hg1−xCdxTe double-layer planar heterostructure (DLPH) large-area detectors is a critical noise component with the potential to limit sensitivi...
-
Article
1/f noise in very-long-wavelength infrared Hg1−xCdx Te detectors
This paper investigates 1/f noise performance of very-long-wavelength infrared (VLWIR) Hg1−xCdxTe (cutoff wavelengths λc=15 µm and λc=16 µm) photodiodes at 78 K, where detector current is varied by changing detec...
-
Article
Advances in large-area Hg1−xCdxTe photovoltaic detectors for remote-sensing applications
State-of-the-art large-area photovoltaic (PV) detectors fabricated in HgCdTe grown by molecular beam epitaxy (MBE) have been demonstrated for the Crosstrack Infrared Sounder (CrIS) instrument. Large-area devic...
-
Article
Current mechanisms in VLWIR Hg1−xCdxTe photodiodes
VLWIR (c∼15 m to 17 m at 78 K) detectors have been characterized as a function of temperature to determine the dominant current mechanisms impacting detector performance. Id−Vd curves indicate that VLWIR detector...
-
Article
Large VLWIR Hg1−xCdxTe photovoltaic detectors
Very long wavelength infrared (VLWIR; 15 to 17 µm) detectors are required for remote sensing sounding applications. Infrared sounders provide temperature, pressure and moisture profiles of the atmosphere used ...
-
Article
Excess low frequency noise/I-V studies in p-on-n MBE LWIR Hg1−xCdxTe detectors
Excess low frequency noise is investigated for the first time in infrared MBE grown LWIR Hg1−xCdxTe double layer planar heterostructure (DLPH) detectors grown on lattice matched substrates. LWIR detectors having ...
-
Article
Arsenic incorporation in MBE grown Hg1−xCdxTe
The p-type do** of Hg1−xCdxTe (MCT) has proven to be a significant challenge in present day MCT-based detector technology. One of the most promising acceptor candidates, arsenic, behaves as an amphoteric dopant...
-
Article
Microscopic defects on MBE grown LWIR Hg1−xCdxTe material and their impact on device performance
Long wavelength infrared molecular beam epitaxy (MBE) grown p-on-n Hg1−xCdxTe double layer planar heterostructure (DLPH) detectors have been characterized to determine the dominant mechanisms limiting their perfo...
-
Article
MBE growth and characterization of in situ arsenic doped HgCdTe
We report the results of in situ arsenic do** by molecular beam epitaxy using an elemental arsenic source. Single Hg1−xCdxTe layers of x ∼0.3 were grown at a lower growth temperature of 175°C to increase the ar...
-
Article
Analysis of the variation in the composition as a function of growth parameters in the MBE growth of indium doped Hg1−xCdxTe
Compositional changes induced in growing Hg1−xCdxTe layers as a function of the changes in temperature of the indium source in the MBE chamber have been analyzed in terms of the Hg-In alloy thermodynamics and cha...
