Multicolor (UV-IR) Photodetectors Based on Lattice-Matched 6.1 A II/VI and III/V Semiconductors

Abstract : This program focused on the demonstration of a novel idea to use optical biasing for multi-color detection using two-terminal monolithically integrated multi-junction photodetectors (MJPDs). Using optical biasing, any sub-photodetector can be selected to limit the current and the multi-color photodetector detects light within the wavelength range of the selected sub-photodetector, namely, optical addressing. This idea has been firstly demonstrated in a monolithic GaInP/Ga(In)As/Ge triple-junction solar cell. Later on, the optical addressing has been achieved in a near-and-long-wave infrared multiband photodetector integrated by a NIR AlGaAs/GaAs PIN sub-photodetector and a LWIR AlGaAs/GaAs n-QWIP sub-photodetector. Finally, the optical addressing has been realized in a visible-and-mid-wave-infrared multi-color photodetector based on II-VI and III-V semiconductors. This photodetector consists of a newly-proposed CdTe/ZnTe/CdTe nBn sub-photodetector for visible light detection and a well-developed InSb PIN sub-photodetector forMWIR detection, which are electrically connected by a perfectly conductive n-CdTe/p-InSb tunnel junction.