Space charge spectroscopy in Hg1-xCdxTe n+-p photodiodes

Abstract

We report an experimental study of thermally stimulated trap phenomena in Hg1-xCdxTe photodiodes. Three experimental spectroscopic techniques have been used to characterize the trapping and emission of carriers at deep energy levels located within the space charge region or n+-on-p junction photodiodes. This study utilized both the synchronous-detection methods of Deep Level Transient Spectroscopy (DLTS) and Admittance Spectroscopy (AS) as well as the single-shot techniques of Thermally Stimulated Current (TSC) and Thermally Stimulated Capacitance (TSCap). Application of these techniques in a complementary approach has identified a single dominant mid-gap recombination center in p-Hg1-xCdxTe (0.2 < × < 0.4). Further, the diode electrical properties p-side minority carrier lifetime τ, dynamic resistance-area product at zero bias voltage RoA, and reverse-bias leakage current were shown to be directly related to a single bulk, donor-like, Shockley-Read recombination center which was identified by space charge spectroscopy.