Temperature and electron concentration dependences of 1/f noise in Hg1−xCdxTe – evidence for a mobility fluctuations mechanism

Abstract

Hg_1−xCd_xTe is a unique material with its bandgap being tunable by temperature, pressure, and cadmium content over a wide range, from 1.6 eV to an inverted bandgap of −0.3 eV. This makes Hg_1−xCd_xTe one of the key materials for infrared and terahertz detectors, whose characteristics largely depend on the material's noise properties. In this work, we investigated the low-frequency 1/f noise in a thick (800 nm) HgCdTe layer and in a field effect transistor (FET) with an 8 nm wide HgTe quantum well. Both structures exhibited a small contribution from contact noise and showed weak noise dependences on temperature. Investigation of the 1/f noise in the HgTe quantum well FET as a function of gate voltage revealed that the noise also depends weakly on electron concentration. These findings indicate that the noise properties of Hg_1−xCd_xTe are similar to those of graphene, where mobility fluctuations were found to be the dominant mechanism of the 1/f noise.