No abstract

No abstract

The stationary photoconductivity and kinetic characteristics in semi-insulating GaAs compensated by oxygen and chromium are investigated : namely, stationary photoconductivity and intrinsic photocurrent optical quenching spectra in the region 0.45 to 1.5eV, temperature quenching and current-light intensity characteristics of the stationary photocurrent, and the kinetics of the photocurrent decay under intrinsic and impurity photoexcitation. The results obtained are interpreted taking into account fast (8) and slow (r) recombination channels. From the analysis of these dependences a number of main parameters of r and s recombination centres is determined: the energy position of the r and s centres (Evr,& the ratio of hole to electron capture cross-section a t r centres (Spr/Sm), the values of Snr and 8as well as the concentration (N,), and initial hole occupation (P:) of r centres. The nature of r and s centres in GaAs (0) and GaAs (Cr) is discussed. klccneAodaHH cTaqHoHapHare H KmxenirecKtie xapamepHcTam @OTO~POBOJIH-MOCTH B nOJIyU30JIXipyIoWeM GaAs, KOMneHCUpOBaHHOM KIICJIOPOAOM El XPOMOM : CIleHTpbI CTaUUOHapHOfi @OTOnPOBOAHMOCTH H OnTH9eCKOr0 I'aIUeHHR CO6CTBeH-H O r O @OTOTOKa B o6nac~H 0,45 L[O 1,s 3B, TeMnepaTypHOe I'aIueHHe H n A X CTaUHO-HapHor0 @OTOTOKa, KHHeTHKa CIlaAa (POTOTOKB B o 6 n a c~~ CO6Cf3eHHOrO H IIpHMeC-H O r O @OTOB036ym~eHHfl. n0JIyWHHble pe3yJIbTaTH HHTepIIpeTHpyIOTCJl C y9eTOM ~H C T P O~O ( 8 ) Xi MeJXJIeHHOrcU (r) KaHaJIOB peKOM6HHaUIIH. kl3 aHaJlH3a yKa3aHHLdX 3aBHCHMOCTefi HafineH PRA OCHOBHHX IlapaMeTpOB r & l 8-qeHTPOB peKOM6HHaqUII : 3JleKTPOHOB II AbIPOK r-IIeHTpaMH (#pr/&), BeJIUqH;bI #m H' 8,,s .a TaK?Ke KOHUeH-TpaUHH (N,) EI HaqaJIbHOe 3aIIOJIHeHHe L[HpKaMH (P!) r-qeHTPOB. 06CymAaeTCfl a~e p r e~~i r e c~o e nonoxiemie r-a s-qeHTpoB (Evp,s), OTHomenne ceremfi 3 a x~a~a npHpoAa r-II s-qeHTpoB B GaAs(0) H GaAs(Cr).

The electric‐field‐induced switching effect to the highly conducting state in ZnSe—Cu, I ceramics is investigated. A possibility is shown to control voltage and switch‐on time by using simultaneous illumination from the impurity absorption region in the spectral range hv ≧ 0.36 eV. The switching effect kinetics and arising electroluminescence peculiarities are studied. Due to the electroluminescence at λmax ≈︁ 530 nm the electric current filaments may be observed. The principal features of the phenomenon are interpreted in terms of a double injection in the device with symmetric contacts when the resistance is modulated according to the τp‐mechanism. The scheme of switch‐initiating deep recombination centres coincident with that proposed earlier for ZnSeCu single crystals is discussed.

The influence of the plastic deformation on the magnetic susceptibility of molybdenum and zinc has been studied. It is found that a sharp increase of the paramagnetic susceptibility after the compression deformation essentially depends on the state of the crystal surface before deformation. The chemical removal of the surface layer leads to disappearing of the observed effect. A concept of connection of arising unusual magnetic behavior of molybdenum and zinc with appearance of microcracks in the surface layer under deformation is proposed. Microcracks are supposed to lead to anomalously high magnitudes ofthe magnetic susceptibility.