Radiolysis of ZnSe(Te, O) scintillators at neutron- and gamma-irradiation

Abstract

Scintillating parameters of isovalently doped ZnSe(Te, O) crystals depend strongly on intrinsic point defects and impurities and deteriorate at different irradiations, because of structure damage. Study of ZnSe(Te, O) crystals with radiometric X-ray and instrumental neutron activation analyses (INAA) has showed that all samples had significant as-grown non-stoichiometry: ~ 49% Se and ~ 51% Zn, while the ideal stoichiometric ratio for ZnSe is 54.7% Se and 45.3% Zn. When doping with 0.5% Te, the impurity was found to be distributed non-evenly over the bulk with two maxima at -0.5 and = 0.25%, while at lower doping levels Te ions were distributed evenly. During ~/-and neutron irradiation up to 10 -5 g of ZnSe at ratio 50-60% Zn and 40-50% Se emitted from the surface due to radiolysis. This is the reason of weakening the luminescence delete.

Photoconductivity of gamma-irradiated Znse (Te)/ZnO:O and ZnSe(Te)/ZnO:O,Zn nanogeterojuctions

“…It can be seen that HT in zinc vapor led to an increase in the electronic conductivity at 90 K by four orders of magnitude, that is σ = 3.3 10 -9 Ohm -1 cm -1 with Ea <0.01 eV. Further, in the range 180 -390 K, there was a decrease to Tmin = 302 K and σmin = 4.110 -10 Ohm -1 cm -1 with Ea = 0.17 eV (Table III), this may be due to an increase in the concentration of VZnTeSeZni defects [23] and the formation of inclusions of the amorphous phase up to 0.9 nm (Table I). Decrease in σ (Т) NHJ ZnSe(Te)/ZnO:O,Zn in 90÷390 K led to an increase in Ea from <0.01 to 0.17 eV, which agrees with the data on the electrical conductivity of a thin ZnSxSe1-x film, where it falls from 300 to 500 K with increasing S content, but Ea of hops increases from 0.13 to 1.89 eV [17].…”

“…After gamma irradiation with ZnSe(Te)/ZnO:O NHJ in the range 90 -190 K, the value of σ = 3.1 10 -12 Ohm -1 cm -1 did not depend on temperature, and at 190 -280 K it began to decrease to 0.5 10 -12 Ohm -1 cm -1 Ea = 0.03 eV in the region of electronic conductivity (curve 2), that is, carriers were localized on associates. In the range 300 -390 K, ionic conductivity with the participation of Zni 5.6 10 -11 Ohm -1 cm -1 with Ea = 0.473 eV is switched on (Table III) and the maximum intensity of electroluminescence (EL) is reached at 72 V [23]. Accordingly, Ne decreases to 4.610 15 cm -3 at 300 K (Table 2).…”

“…For NHJ ZnSe(Te)/ZnO:O,Zn, the dark blocking voltage decreased to 6 V, respectively, R decreased by three orders of magnitude, due to an increase in the concentration of VZnTeSeZni associates [19], and the voltage range of the rectifying property decreased from -17 +10 V, and EL appears already at 8 V [23], which may be associated with the formation of an amorphous ZnO phase with a characteristic size of up to 0.9 nm on the ZnSe surface. According to [16], the n-GaР-n + -(ZnSe)1-x-y(Si2)x(GaР)y heterostructure in the range of rectifying voltages from -20 + 15 V gave visible glow from 10 V. After illumination, the I -V characteristic acquires photodiode structure, with σPhC up to 210-8 Ohm -1 (Table IV).…”