Nonuniform quantum well infrared photodetectors

Abstract

A nonuniform quantum well infrared photodetector (QWIP) structure is proposed. By changing the doping concentration and barrier width of each quantum well, the electric field distribution can be tailored. The nonuniform QWIPs show excellent performance compared with conventional uniform structures. The dark current is about an order of magnitude lower and the background limited temperature increases to 77 K. A detectivity of 2.0x10(10) cm Hz(1/2)/W and a responsivity of 0.25 A/W at 8.2 mu m have been obtained for these devices. A simple picture of electric field distribution within the structure is described to explain the results. (C) 2000 American Institute of Physics. [S0021-8979(00)07701-X].