LOW DARK CURRENT INFRARED HOT-ELECTRON TRANSISTOR FOR 77-K OPERATION

Recently, thermal imaging using quantum well infrared photodetector (Q WIP) focal plane arrays has been demonstrated. However, the operating temperature needs to be kept around 60 K due to the large dark current occurring at higher temperatures. In order to achieve thermal imaging at 77 K, we have designed and demonstrated two infrared hot-electron transistor structures, whose dark current is two to three orders of ma gnitude lower than that of a QWIP. The resultant dark current falls wi thin the limit of the charge handling capacity of a readout circuit, a nd the infrared detection is demonstrated to be background limited at 77 K. The noise equivalent temperature difference of the detectors is estimated to be 14 and 26 mK, respectively.