V. A. Zhitov

Deposition of heteroepitaxial layers of topological insulator Bi2Se3 in the trimethylbismuth–isopropylselenide–hydrogen system on the (0001) Al2O3 and (100) GaAs substrates

Thin solid layers that are formed upon heating of the gaseous trimethylbismuth–isopropylselenide–hydrogen system on the (0001) Al2O3 and singular and vicinal (100) GaAs surfaces are studied. The conditions for deposition of metal Bi and phases of Bi4Se3, BiSe, and topological insulator Bi2Se3 using the MOCVD method are determined. Pure metastable phase BiSe is obtained for the first time. Bi2Se3 films with a thickness of no less than 200 nm, a relatively low volume concentration of 3 ×1018 cm–3, and a high mobility of carriers at 300 K (1000 cm2 V–1 s–1) are fabricated.

MSM optical detector on the basis of II-type ZnSe/ZnTe superlattice

On the basis of a type-II ZnSe/ZnTe superlattice, a MSM (metal—semiconductor–metal) photodetector is fabricated and investigated. The detector features low dark currents and a high sensitivity. The spectral characteristic of the detector provides the possibility of the selective detection of three separate spectral portions of visible and near-infrared radiation.

Solar Blind MSM-Photodetectors Based on Al x Ga 1-x N/GaN Heterostructures Grown by MOCVD

The MOCVD technology of semiconductor heterostructures for ultraviolet photodetectors was developed. Solar blind AlGaN/GaN MSM photodetectors were fabricated and investigated. Directly on the MSM-diode we have measured a Schottky barrier height of 1.1 eV for Ni and 1.4 eV for Mo contacts on AlGaN. Effect of different buffer layers on the detector performances has been demonstrated. Detectors exhibit low dark currents and high sensitivity within the range of 250 - 290 nm. Effect of high optical excitation level on detector performance is discussed.

Selective UV radiation detection on the basis of low-dimensional ZnCdS/ZnMgS/GaP and ZnCdS/ZnS/GaP heterostructures

The detecting properties of periodic heterostructures with ZnCdS quantum wells separated by ZnMgS or ZnS barrier layers are studied. Heterostructures are grown on semi-insulating GaP substrates by metal organic vapor-phase epitaxy (MOVPE). On their basis, metal–semiconductor–metal (MSM) diodes with interdigital Schottky contacts 3 μm, distances between them of 3 μm, and a total detector area of 100 × 100 μm are fabricated. The detectors have low dark currents (10–12 A); at low bias voltages, they provide a narrow- band response (full-width at half-maximum of FWHM = 18 nm at a wavelength of 350 nm) which is controlled by the ZnCdS quantum-well composition. As bias is increased to 70 V, the maximum detector sensitivity shifts by a wavelength of 450 nm, which is caused by penetration of the external-bias electric field into the semi-insulating GaP substrate. In this case, the narrow-band response of the detector at a wavelength of 350 nm is retained, i.e., the two-color detection of light is provided.