Effect of the microwave radiation treatment of porous indium phosphide on spectra of radiative recombination centers

To study the influence of microwave irradiation on a spectrum of defect states in porous InP, we have measured the luminescence spectra within the range 0.50 to 2.04 eV at 77 K before and after short and long (up to 600 s) treatments in air in the operation chamber of a magnetron at a frequency of 2.45 GHz and a surface power density of 7.5 W/cm² . We have obtained that the spectra of defects in researched samples are essentially changed as well as the concentrations of local centers. Possible mechanisms of observable changes in the semiconductor impurity-defect composition caused by a microwave treatment are discussed

Effect of low magnetic field treatment on spectra of radiative recombination centers in indium phosphide structures

We present the results of investigations of the effect caused by low magnetic field treatment on InP single crystals impurity-defect composition. This effect was found when studying the radiative recombination (luminescence) spectra in the 0.6-2.5 µm range at 77 K. The static magnet with B = 0.44 T was used as a source of magnetic field. We studied samples of two groups: porous InP crystals and epitaxial layers grown on porous substrate. The crystals of both groups were not specially doped. It has been obtained that treatment even for 0.02 min resulted in considerable changes in luminescence spectra. The luminescence intensities after treatment increase at first, but later behavior is nonmonotonic: next treatment can result in decrease or increase a value of intensities of both observed bands. It should be noted that the luminescence intensities of epitaxial layers, perhaps, changed as well as concentration of nonradiative centers changed. But for porous indium phosphide, these features were not observed

Diameter-dependent thermopower of Bi nanowires

We present a study of electronic transport in individual Bi nanowires of large diameter relative to the Fermi wavelength. Measurements of the resistance and thermopower of intrinsic and Sn-doped Bi wires with various wire diameters, ranging from 150-480 nm, have been carried out over a wide range of temperatures (4-300 K) and magnetic fields (0-14 T). We find that the thermopower of intrinsic Bi wires in this diameter range is positive (type-p) below about 150 K, displaying a peak at around 40 K. In comparison, intrinsic bulk Bi is type-n. Magneto-thermopower effects due to the decrease of surface scattering when the cyclotron diameter is less than the wire diameter are demonstrated. The measurements are interpreted in terms of a model of diffusive thermopower, where the mobility limitations posed by hole-boundary scattering are much less severe than those due to electron-hole scattering.Comment: 32 pages, 12 figures. Previous version replaced to improve readabilit

Effect of microwave irradiation on radiative recombination of GaAs

The paper considers the impact of powerful short-term microwave radiation (f= 2.45 GHz) on the defect states of GaAs monocrystals by investigating the luminescence spectra in a domain of 0.6–2.5 μm at 77 K. It has been found experimentally that microwave treatment affects the luminescence characteristics of crystals due to variation of concentration of centers of radiative and nonradiative recombination. The results of the inquiries show advantages of application of microwave radiation in technological processes for modification of the impurity-defect subsystem of semiconductor materials

The impact of microwave radiation on radiative recombination of CdS

The paper considers the impact of a powerful short-term microwave radiation (f= 2.45 GHz) on defect states of CdS monocrystals with the aid of investigation of the luminescence spectra in a domain of 0.6–2.5 μm at 77 K. It has been found experimentally that the microwave processing affects the luminescence characteristics of the crystals because of a change in concentration of cation vacancies (centers of photosensitivity) and in concentration of centers of fast (nonradiative) recombination. The results of the investigations point to the prospects in applying the microwave radiation in technological processes for the control of photosensitivity and of the luminescence spectra of cadmium chalcogenide