Optical absorption of un-implanted and implanted HgCdTe

Abstract

Optical absorption coefficients of un-implanted and implanted HgCdTe have been measured in a range of temperatures and compositions. The index of refraction for photon energies larger than bandgap was obtained. With the measured index of refraction, large values of the optical absorption coefficient were extracted from measured transmission spectra. The obtained optical absorption coefficient agrees very well with the Kane's model. The measured optical absorption coefficient at the bandgap linearly depends on temperature. Cutoff photon energy for highly n-type doped HgCdTe resulted from ion implantation of boron at 150 keV energy and with 1 × 10 15 cm -2 dose is larger than that for the un-implanted HgCdTe. The magnitude of the shift is consistent with the prediction of the theory of Moss-Burstein shift, using measured doping profile.

Spectral sensitivity dependencies of backside illuminated planar MCT photodiodes

“…Minor reflections at GaAs/CdZnTe and CdZnTe/ HgCdTe boundaries were not taken into account. When calculating the reflection coefficient R 1 for outer boundary part of MCT layer the spectral dependence of refractive index t n(k) [7] was taken into account (e.g., nðk Eg Þ % 4).…”

“…Here m hh and m lh are the effective masses of heavy and light holes, respectively. When calculating the absorption coefficient a hh and a lh spectral dependence of refractive index n(k) [7] was taken into account. Exponential optical absorption connected with internal electric fields is due, e.g., to impurities present, chemical composition fluctuations, etc., and due to longitudinal optical phonons with their temperature dependent distribution.…”

Process modeling of HgCdTe infrared photodetectors

“…8,9 The remainder of this paper describes the models, capabilities, and uses of the process simulators in more detail. As part of the Infrared Focal Plane Array, Flexible Manufacturing (IRFPA/ FM) Program, the Helms Group at Stanford University developed a suite of software tools for simulating the processing, device characteristics, and perfor-mance of HgCdTe based infrared detectors.…”