A noncontact, noninvasive lifetime characterization technique for measuring the excess carrier lifetime in long wavelength infrared (LWIR) Hg_1-xCd_xTe (x approximately equals 0.20-0.225) using transient millimeter-wave (90 GHz) reflectance is presented. Excess carrier lifetime results for both p-type (vacancy-doped >= 1 X 10¹⁶ cm^-3) and n-type (annealed <= 1x10¹⁵ cm^-3 epilayer material are given. The lifetimes in vacancy-doped p-type HgCdTe are short, i.e., approximately 25 ns at 80 K, thereby requiring a short-pulsed laser source and high-bandwidth electronics in the lifetime test system. The lifetime test system employs either YAG (1.06 micrometers ) or CO₂ (9-11 micrometers ) pulsed laser excitation. Lifetime results for both frontside and backside laser illumination of the epilayer HgCdTe are presented. The effect of surface recombination of lifetime and reflected millimeter-wave signal amplitude is discussed.

Date Published: 1 August 1991
PDF: 12 pages
Proc. SPIE 1484, Growth and Characterization of Materials for Infrared Detectors and Nonlinear Optical Switches, (1 August 1991); doi: 10.1117/12.46503

Published in SPIE Proceedings Vol. 1484:
Growth and Characterization of Materials for Infrared Detectors and Nonlinear Optical Switches
Randolph E. Longshore; Jan W. Baars, Editor(s)