Magnetophotoconductivity of semi-insulating GaAs and its behavior upon electron bombardment

The effect of a magnetic field on the photoconductivity of semi-insulating p-type GaAs single crystals mounted in the Voigt geometry has been investigated within the temperature region 260-350°K. If the magnetic field deflects the photocarriers toward the volume of the specimen, a decrease of the photoconductivity is obtained for weak electric field and an increase for high electric field under constant magnetic field. The decrease is attributed to the combination of photoconductivity and photomagnetoelectric effect while the increase is attributed to the difference in the values of lifetime across the specimen thickness. From photoconductivity measurements with and without the application of magnetic field, the carrier lifetimes were determined. Bombardment of the specimen with 1-MeV average energy β particles resulted in a decrease of the magnetophotoconductivity at high electric fields. © 1972 The American Institute of Physics

Behavior of magnetophotoconductivity of semi-insulating GaAs upon α-particle bombardment

The effect of 2-MeV α-particles on the magnetophotoconductivity of semi-insulating GaAs single crystals mounted in the Voigt geometry has been investigated at 300°K. Upon bombardment of the specimen we found an increase of the positive branch of the magnetophotoconductivity while the negative branch remained unaltered. The increase is attributed to a decrease of carrier lifetime in the damaged surface region. The negative branch remains constant since the α-particles do not influence the bulk properties. © 1973 American Institute of Physics

Spectrum of light emitted from ZnCdS: Ag screens excited by an electron beam

The emission spectrum of a ZnCdS: Ag phosphor screen excited by an electron beam was measured for different screen's thickness. This spectrum is found to be shifted towards the longer wavelengths when the screen thickness increases. The matching factor a between screen and some commercial photocathodes, which alter because of this shifting, is given as a function of the screen thickness. © 1979 Springer-Verlag

Magnetophotoconductivity of semi-insulating GaAs as a function of etching time

The magnetophotoconductivity of semi-insulating GaAs has been investigated for various etching times. We observed that the carrier lifetime of the illuminated region increases as a function of etching time approaching the bulk lifetime of the non-illuminated region. This was explained on the suggestion that the surface recombination centers gradually disappear as the etching time increases. © 1979

Magnetophotoconductivity of semi-insulating GaAs as a function of etching time

The magnetophotoconductivity of semi-insulating GaAs has been investigated for various etching times. We observed that the carrier lifetime of the illuminated region increases as a function of etching time approaching the bulk lifetime of the non-illuminated region. This was explained on the suggestion that the surface recombination centers gradually disappear as the etching time increases. © 1979

Temperature dependence of ZnCdS: Ag cathodoluminescence efficiency under electron beam excitation

The temperature dependence of the efficiency of ZnCdS: Ag phosphor excited by a constant electron beam was investigated. Three well expressed maxima were observed at temperatures of about 60, 160, and 230 K. © 1983 Springer-Verlag

Temperature dependence of mobilities and carrier concentrations in semi-insulating GaAs

The temperature behavior of electron and hole mobilities and carrier concentrations was measured in p-type Cr doped semi-insulating GaAs. The above quantities were determined by measuring at a given temperature the photomagnetoresistance and photo-Hall effect vs magnetic field intensity. A minimum of hole concentration is observed at 210-225 K. The electron concentration either remains constant below 190-200 K or it rises again at lower temperatures. The mobilities of both carriers show a maximum at almost the same temperatures with those where the behavior of n and p changes. We try to explain the above on the basis of radiative recombination and impurity conduction. © 1980