Detectivity Enhancement in Cascade Infrared Upconverter Utilizing AlInP Hole-Blocking Layer.

A cascade infrared upconverter (CIUP) avoids mechanical bonding between photodetectors and read-out integrated circuits, being a promising candidate for very large-format infrared imaging. This letter demonstrates a CIUP with an Al0.52In0.48P hole-blocking layer whose valence band discontinuity with GaAs is large, which will tightly confine injected holes into the emission region. The device shows a peak response wavelength at 4.9~\mu \textm and a peak emission wavelength at 870 nm. At 1.4 V bias and 78 K, shot noise limited detectivity of the upconversion system is 1.17\times 10^9 Jones, about one order of magnitude higher than the previously reported CIUP with an AlAs hole-blocking layer. [ABSTRACT FROM PUBLISHER]