Low‐frequency noise and deep‐level transient spectroscopy in LWIR Auger‐suppressed Hg_1-xCd_xTe heterostructure detector

Abstract

Low-frequency noise spectroscopy (LFNS) along with deep-level transient spectroscopy (DLTS) are complementary and effective tools to study and characterize the carrier traps in semiconductors. These traps caused, e.g., by contamination by foreign atoms or various types of dislocations, can significantly affect quantum efficiency, dark current, responsivity, and noise generated by devices especially when operating under bias. Since DLTS is difficult to apply in high leakage current devices, LFNS can be used to overcome this limitation, so the use of both methods gives very effective and reliable results during research on various devices. In this paper, we reported a study of defects activation energies in HgCdTe Auger-suppressed long-wavelength infrared (LWIR) heterostructure-based detector using these two experimental methods. By proper structure design, the examined detector was optimized for high operating temperature (HOT) conditions ≥ 200 K. The results obtained showed that in such detectors, grown by the metal organic chemical vapor deposition (MOCVD) technique, a few traps can be extracted. The found trap levels and activation energies were located below and above the absorber bandgap, so they can be identified in both absorber and other heterostructure layers. Due to specific multilayer architecture, a precise interpretation of the results is difficult. Nevertheless, the most probable trap locations based on the current state of knowledge were discussed and proposed.