4.3 THz quantum-well photodetectors with high detection sensitivity**Project supported by the National Key R&D Program of China (Grant No. 2017YFF0106302), the National Basic Research Program of of China (Grant No. 2014CB339803), the National Natural Science Foundation of China (Grant Nos. 61404150, 61405233, and 61604161), and the Shanghai Municipal Commission of Science and Technology, China (Grant Nos. 15JC1403800, 17ZR1448300, and 17YF1429900).

Abstract

We demonstrate a high performance GaAs/AlGaAs-based quantum-well photodetector (QWP) device with a peak response frequency of 4.3 THz. The negative differential resistance (NDR) phenomenon is found in the dark current–voltage (I–V) curve in the current sweeping measurement mode, from which the breakdown voltage is determined. The photocurrent spectra and blackbody current responsivities at different voltages are measured. Based on the experimental data, the peak responsivity of 0.3 A/W (at 0.15 V, 8 K) is derived, and the detection sensitivity is higher than 1011 Jones, which is in the similar level as that of the commercialized liquid-helium-cooled silicon bolometers. We attribute the high detection performance of the device to the small ohmic contact resistance of and the big breakdown bias.