Author(s): Jia, CY (Jia, Chun -Yang); Deng, GR (Deng, Gong-rong); Zhao, P (Zhao, Peng); Zhu, ZZ (Zhu, Zhi-zhen); Zhao, J (Zhao, Jun); Zhang, YY (Zhang, Yi -Yun)

Source: JOURNAL OF INFRARED AND MILLIMETER WAVES Volume: 43  Issue: 2  Pages: 166-173  DOI: 10.11972/j.issn.1001-9014.2024.02.004  Published Date: 2024 APR  

Abstract: The demand for high-speed response mid -wave infrared (MWIR ) photodetectors (PDs ) is gradually increasing in emerging fields such as free -space optical communication and frequency comb spectroscopy. The XB n n barrier infrared 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 atomic force microscopy (AFM ) results indicate that both epitaxial structures exhibit good crystal quality. The 90 gm diameter pBn PDs exhibit a lower dark current density of 0. 145 A/cm 2 compared to the nBn PDs operating at room temperature (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 absorption region , while the nBn absorption region also exhibits partial depletion. RF response characterization demonstrates that the 90 mu m 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.