Electrophysical properties of photosensors based on radiation-resistant Hg2MnInTe6 crystals

Abstract

Electro-physical properties of Cr/Hg2MnInTe6/In photosensors with a surface nanostructure (SNS) created by a special surface treatment were measured in this work. With this treatment, the surface lost its mirror-like shine and was perceived as matte. For comparison, the fabrication of a Au/Hg2MnInTe6/In structure on a mirror surface was also performed. Hg2MnInTe6 single crystals were grown by modified zone melting and have an electronic type of conductivity with a band gap equal to Eg=1.21 eV and a high resistivity ρ≈2•10 7 Ω×cm (at 293 K), which was determined from the linear section of the I-V curves. The initial section of the I-V curve for Cr/Hg2MnInTe6/In at reverse bias (0.1 -10 V) could be described within the framework of the Sah-Noys-Shockley model. At voltages greater than 10 V, a linear dependence of the I-V curve was observed, and at voltages greater than 200 V, currents limited by space charge (CLSC) were observed. Cr/Hg2MnInTe6/In photosensors with SNS (matte surface) had significantly better electro-physical parameters than Au/Hg2MnInTe6/In photosensors (mirror surface): smaller dark currents, higher rectification coefficient, and higher current monochromatic sensitivity. For example, at 1 V, the dark current for Au/MMIT/In is equal to I=29 nA, and for Cr/MMIT/In, the dark current is I=2 nA. At a voltage of U=10 V, the dark currents are 150 nA and 7 nA, respectively. The rectification coefficient for Cr/Hg2MnInTe6/In at 10 V was К≈40, and for Au/Hg2MnInTe6/In it was К≈7. Due to the surface treatment before depositing rectifying contacts, the current monochromatic sensitivity Sλ for structures of Cr/Hg2MnInTe6/In reached a maximum at a wavelength of λ≈1.15 μm and was equal to Sλ≈3 A/W, and for Au/Hg2MnInTe6/In the sensitivity Sλ≈0.8 A/W.