Фотоэлектрические свойства монокристаллов MnGaInS-=SUB=-4-=/SUB=-

The spectral distribution of photoconductivity and the temperature dependence of the photocurrent of monocrystals MnGaInS4 are studied. The intrinsic and extrinsic photoconductivities are revealed in the spectrum of photoconductivity. The wavelength range of 0.640–0.760 μm is shown when manganese deficiency in crystals appears and is due to an acceptor defect. The temperature dependence of the band gap in the monocrystals MnGaInS4 is related to the electron – phonon interaction. In the studied temperatures, increase in the photocurrent is associated with the thermal depletion of the attachment levels. The activation energy of the attachment levels is estimated.

Acceptor defect-participating magnetic exchange in ZnO : Cu nanocrystalline film: defect structure evolution, Cu–N synergetic role and magnetic control

Acceptor defect: a more efficient ferromagnetic activation route than donor defect in Zn–Cu–O dilute magnetic semiconductor.

Effect of Growth Atmosphere on the Structural, Optical and Magnetic Properties of Fe-Doped In2O3 Films

Room temperature ferromagnetism was observed in Fe-doped In2O3 films deposited on fused quartz substrates by radiofrequency magnetron sputtering in N2 and O2 atmosphere, respectively. Results show that with increasing the O2 and N2 flux, the lattice constant increases, the optical band gap decreases, and the ferromagnetism weakens. Moreover, the decrease in the saturation magnetization for films deposited in N2 atmosphere is more apparent than that deposited in O2 atmosphere. We think the reason is that in our Fe-doped In2O3 films the ferromagnetism is mainly mediated by the oxygen vacancies, and as an acceptor defect, N ions can decrease the concentration of the oxygen vacancies to a greater extent than the O ions.

Growth, Structural Characterization, and Optical Band Gap Anomaly in Cu-III3-VI5 and Cu-III5-VI8 Ternary Compounds

ABSTRACTA comparative study of the chemical composition, crystal structure, carrier concentration, mobility, and the energy gap at room temperature of the selenides and tellurides of normal Cu- III-VI2 and ordered defect Cu-III3-VI5and Cu-III5-VI8 compounds, grown by Bridgman techniques, is made. It is established that these compounds have a chalcopyrite-related structure with the exception of CuIn5Se8 and CuGa5Te8 that have hexagonal and cubic structure, respectively. Smaller volume of the unit cell and lower concentration of the charge carrier of the 1:3:5 and 1:5:8 phases, as compared to the 1:1:2, are attributed to the presence of the ordered vacancies. A new mechanism of the scattering of the charge carriers with the donor-acceptor defect pair (DADP) is suggested to explain the low value of mobility in these compounds. The anomaly observed in the band gap is explained in terms of the relative shift of the conduction band minimum and valence band maximum due to the donor-acceptor defect pairs and cation vacancies, respectively.