Far-Infrared Detector Based on HgTe/HgCdTe Superlattices
Authors: Zhou, Y.D.; Becker, C.R.; Selamet, Y.; Chang, Y.; Ashokan, R.; Boreiko, R.T.; Aoki, T.; Smith, David J.; Betz, A.L.; Sivananthan, S.
Source: Journal of Electronic Materials, Volume 32, Number 7, 1 July 2003 , pp. 608-614(7)
Abstract:HgTe/Hg0.05Cd0.95Te superlattices (SLs) were grown on (112)B oriented Cd0.96Zn0.04Te substrates using molecular beam epitaxy (MBE). The SLs, consisting of 100 periods of 80-Å-thick HgTe wells alternating with 77-Å-thick Hg0.05Cd0.95Te barriers, were designed to operate as detectors in the far-infrared (FIR) region. Infrared absorption spectroscopy, high-resolution transmission electron microscopy (TEM), Hall effect measurements, and x-ray diffraction were used to characterize the superlattice layers. A series of annealing experiments were initiated to quantify the temperature-dependent interdiffusion of the HgTe wells and Hg0.05Cd0.95Te barriers and consequently their degradation, which shifts the absorption edges of the SLs to higher energies, since a high-temperature ex situ anneal is normally required in order to produce the p-type material required for a photovoltaic detector. Results from infrared absorption spectroscopy, TEM, and Hall effect measurements for the annealed samples are presented. A FIR SLs single-element photoconductive (PC) device was designed and fabricated. Both material characterization and device testing have established the applicability of the HgTe/Hg0.05Cd0.95Te SLs for the FIR region.
Document Type: Research Article
Publication date: 2003-07-01