Demonstration of Far-Infrared GaAs/AlGaAs Quantum Well Photodetectors for Broadband Wavelength Detection

Abstract

We discuss the realization of broadband wavelength detection by demonstrating the longest cutoff wavelength (A, = 28.6 pm) far-infrared GaAs/AJGaAs quantum well infrared photodetectors (QWIPs). The responsivity is comparable to that of mid-infrared GaAs/AlGaAs and InGaAs/GaAs QWIPs, with a responsivity of 0.265A/W and detectivity of 3 . 4 ~1 0 ' cm.Hz1I2/W at the peak wavelength of 26.9pm at 4.2K. Based on the temperaturedependent dark current and response results, it is expected that similar performance can be obtained at least u p to 20 K. Several ways to expand the wavelength coverage are also addressed.