Quaternary photodetector for downhole optical sensing

摘要

Detector assembly for downhole spectroscopy includes a near-infra-red quaternary photodiode that can operate at high temperatures without cooling it to the standard operation temperature range of the photodiode. High temperature operation of the photodiode right shifts the detector assembly's responsivity curve to include wavelengths of up to 2400-nm. The photodiode has manageable dark current at temperatures even at 200°C, and it can be packaged using high temperature construction. The photodiode is operated in photovoltaic mode at high temperatures but can be operated at photoconductive mode at lower temperatures. At least partial cooling can be provided above a predetermined temperature.