W-structured type-II superlattice long-wave infrared photodiodes with high quantum efficiency

作者：E. H. Aifer, Joseph G. Tischler, Jeffrey H. Warner, I. Vurgaftman, W. W. Bewley, J. R. Meyer, J. C. Kim, Lloyd J. Whitman, Chad L. Canedy, Edward M. Jackson · 发表于：Applied Physics Letters · 年份：2006 · DOI：10.1063/1.2335509 · 被引用次数：127 · 研究领域：Advanced Semiconductor Detectors and Materials、Semiconductor Quantum Structures and Devices、Spectroscopy and Laser Applications

Results are presented for an enhanced type-II W-structured superlattice (WSL) photodiode with an 11.3μm cutoff and 34% external quantum efficiency (at 8.6μm) operating at 80K. The new WSL design employs quaternary Al0.4Ga0.49In0.11Sb barrier layers to improve collection efficiency by increasing minority-carrier mobility. By fitting the quantum efficiencies of a series of p-i-n WSL photodiodes with background-doped i-region thicknesses varying from 1to4μm, the authors determine that the minority-carrier electron diffusion length is 3.5μm. The structures were grown on semitransparent n-GaSb substrates that contributed a 35%–55% gain in quantum efficiency from multiple internal reflections.