Engineering the Bandgap of Unipolar HgCdTe-Based nBn Infrared Photodetectors

• DOI: 10.1007/s11664-014-3511-9
• Publication Date: 2014-12-02T16:33:05Z
• Authors: M. Kopytko; J. Wróbel; K. Jóźwikowski; A. Rogalski; J. Antoszewski; N. D. Akhavan; G. A. Umana-Membreno; L. Faraone; C. R. Becker
• Keywords: Depletion region; Band offset; Barrier layer; Rectangular potential barrier

Design of practically realizable unipolar HgCdTe nBn photodetectors has been studied in detail by numerical analysis. The simulations reported herein reveal that, optimization barrier doping, dark current levels can be reduced and collection efficiency substantially improved. It is shown that p-type doping the layer significantly reduce effective potential arising from valence band offset between absorber regions, thus enabling detector operation under near zero-bias conditions. However, relatively high electric fields space charge regions barrier/absorber interface result enhanced trap-assisted Shockley–Read–Hall thermal generation. Our calculations indicate detectors with barriers engineered use HgTe/Hg0.05Cd0.95Te superlattices have, potentially, better alignment without need for doping.