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 μm 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.
This paper reports the fabrication details of ion-implanted Si:P blocked-impurity band photodetectors with lateral structure. A set of performance data has been measured under the operating temperature of 5.5 K. The device exhibits good blocking characteristics with low dark current density under 10<sup>−4</sup> A/cm<sup>2</sup>. Linear black-body response has been observed at small bias voltage (1 V) and low temperature (5.5 K) with the peak responsivity of 0.8 A/W. The photocurrent (PC) spectra show response peak at 27.3 μm and extend to 40 μm (~7.5 THz), which indirectly proves the feasibility of the preparation of Si:P BIB detectors using ion implantation. In addition, other small features in the PC spectra are designated to associate with the photothermal ionization and the silicon phonon absorption processes. Our work provides an alternative convenient approach to fabricate Si:P BIB detector for far-infrared and terahertz radiation detection.