Investigation of a multistack voltage-tunable four-colorquantum-well infrared photodetector for mid- and long-wavelengthinfrared detection

摘要

A four-color quantum-well infrared photodetector (QWIP) for mid-nand long-wavelength infrared (MWIR and LWIR) detection has beenndemonstrated in this work. Four stacks of QW structures with fourndifferent detection wavelengths are sandwiched between three highlyndoped contact layers. Peak detection wavelengths of this device arencentered at 4.7, 8.5, 9, and 12.3 Μm, respectively. The 4.7- andn8.5-Μm stacks are separated from the 9- and 12.3-Μm stacks by anmiddle contact layer, and the peak detection wavelength within these twondouble-stack QWIP's can be tuned by the applied bias. Four differentncombinations of two-color simultaneous readings can be achieved. Bynusing a small number of QW's and balancing the impedance between thenstacks, we are able to use all four stacks for voltage-tunablenmulticolor detection with two terminals. The bias and temperaturendependence of the dark current and peak responsivity as well as thendynamic impedance in this four-color QWIP were systematically studiednover a wide range of bias and temperature. In spite of using fourndifferent stacks of strained InGaAs-AlGaAs and GaAs-AlGaAs materials,nthe device shows excellent material quality and performance