A 46 μm AlGaAs/GaAs Terahertz Quantum-well Infrared Photodetector

摘要

Recently infrared photodetectors have attracted much attention due to their potential use in infrared imaging, optical communications, medical detection and many other fields. In this letter, we report a THz quantum well infrared detector based on AlGaAs/GaAs material system. Structure with 4% Al content in the barrier was grown using molecular beam epitaxy (MBE). The photocurrent spectra were measured at 4.3 K with a Fourier transforming infrared spectrometer using a solid substrate far-IR beam splitter and the peak response wavelength at 46 urn was observed, close to the theoretical calculated results. The dark currents for the THz QWIP detector have been measured at different temperatures. It was found that there is a huge discontinuity in the current. We analyzed this phenomenon and believed the discontinuity in the current was caused by intersubband impact ionization of the first quantum well.