The demand for high-speed response mid-wave infrared(MWIR)photodetectors(PDs)is gradually increas-ing in emerging fields such as free-space optical communication and frequency comb spectroscopy.The XBnn barrier in-frared photodetectors greatly suppress shot noise originated from the device dark current.In this work,InAsSb/AlAsSb/AlSb-based nBn and pBn barrier MWIR PDs were grown on GaSb substrates using molecular beam epitaxy(MBE).The GSG PDs were fabricated to realize the radio frequency(RF)response testing.X-ray diffraction(XRD)and atom-ic force microscopy(AFM)results indicate that both epitaxial structures exhibit good crystal quality.The 90 μm diame-ter pBn PDs exhibit a lower dark current density of 0.145 A/cm² compared to the nBn PDs operating at room tempera-ture(RT)and a reverse bias of 400 mV,which indicates the uncooled barrier PDs perform with low noise.Capacitance tests reveal that the pBn PDs,operating at zero bias,show a fully depleted barrier layer and partially depleted absorp-tion region,while the nBn absorption region also exhibits partial depletion.RF response characterization demonstrates that the 90 μm diameter pBn PDs achieve 3 dB bandwidth of 2.62 GHz at room temperature and under a 3 V reverse bi-as,which represents a 29.7%improvement over the corresponding nBn PDs,only achieving 3 dB bandwidth of 2.02 GHz.This signifies a preliminary achievement of uncooled barrier MWIR PDs capable of fast detection.
国家科技期刊平台
NSTL
万方数据
