The performance of leading HgCdTe p-n junction infrared (IR) device technology is limited by thermal generationrecombination (G-R) mechanisms and material processing challenges associated with achieving low, controllable in-situ p-type doping using molecular beam epitaxy (MBE) growth techniques. These aspects are addressed in the proposed hybrid HgCdTe NBνN structure which relies on band gap engineered layers to suppress Shockley-Read-Hall (SRH) and Auger G-R processes contributing to performance degradation. The unipolar NBνN architecture provides the desired advantages of a simplified fabrication process, eliminating p-type doping requirements. Physics-based numerical device simulations incorporating established HgCdTe material parameters and G-R mechanisms are used to study the performance characteristics of a long wavelength infrared (LWIR) NBνN device with a 12 μm cut-off wavelength. The calculated results are compared to those values obtained for an LWIR HgCdTe nBn device. Theoretical dark current density (J_dark) values of the NBνN device are lower by an order of magnitude or more for temperatures between 50 K and 245 K. Calculated detectivity (D*) values of 2.367 x 10¹⁴ - 2.273 x 1011 cm Hz^0.5/W for temperatures ranging from 50 K and 95 K, respectively, are observed in the NBνN structure.

Date Published: 16 September 2011
PDF: 6 pages
Proc. SPIE 8155, Infrared Sensors, Devices, and Applications; and Single Photon Imaging II, 81550J (16 September 2011);

Published in SPIE Proceedings Vol. 8155:
Infrared Sensors, Devices, and Applications; and Single Photon Imaging II
Manijeh Razeghi; Paul D. LeVan; Ashok K. Sood; Priyalal S. Wijewarnasuriya, Editor(s)