Junction optimization in HgCdTe: Shockley-Read-Hall generation-recombination suppression
Abstract
Heterojunction device design concepts are leveraged to reduce depletion layer generation-recombination (G-R) dark current in planar P+-on-n SWIR HgCdTe infrared detectors. Shockley-Read-Hall (SRH) depletion dark current (when present) is expected to be the dominant dark current component at low temperatures, and in fact, it is beneficial for the transition from diffusion to G-R to be at such relatively low temperatures. However, it is empirically observed that even for relatively long values of the SRH lifetime (20 μs), the transition occurs at relatively high temperatures (>200 K) for material with a cut-off wavelength of 2.5 μm. A key device design parameter of P+-on-n photodiodes is the position of the electrical junction relative to the hetero-metallurgical interface. Junction formation via p-type arsenic implantation into the narrow-gap absorber layer is typically chosen for efficient collection of diffusion current, however, other configurations are possible as well. In this letter, we numerically explore the conditions that reduce depletion dark current without reducing the quantum efficiency (QE). The findings support the assertion that device design conditions exist in SWIR HgCdTe that essentially eliminate the depletion dark current without significantly reducing the QE.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 13, 2015
- Source ID
- 10.1063/1.4926603
Entities
People
- E. A. Decuir Jr.
- E. Bellotti
- J. Schuster
- P. S. Wijewarnasuriya
- R. E. Dewames
Organizations
- Boston University
- Oak Ridge Associated Universities
- United States Army Research Laboratory