engleski

Recombination effects in gamma-quanta irradiated ZnIn2S4(III)

The gamma-irradiation of ZnIn2S4(III) with 3x10(na17) cm(na-2) doze has been recently shown to achive a structural ordering of its crystalline lattice (Arama E.D. et al, Phys.Stat.Sol.(a), 1988, 109, No 1). Presented in this report is the average photo-response time (tau), conductivity (sigma) in the 293…443 K range, photoluminescence (PL) and other characteristics of the ZnIn2S4(III) crystals gamma-irradiated with a doze of 5x10(na17) cm(na-2). In the 293-343 K range, (sigma) decreases 2 orders of magnitude, whereas (tau) was seen to increase one order of magnitude. It took 2x10(na-4) s and 10(na-2) s for photoconductivity (PC) to decay down to 30% in starting and irradiated samples, respectively. The change of the PC decay curve shapes was seen to depend on the photon energy and intensity of the illumination and on temperature. At 77 K, at a steady state excitation the PL band maximum and its half-width acquire the values 1.73 and 1.63 eV ; 0.49 and 0.41 eV for the starting and irradiated samples, respectively. In case of the latter’s there is also a significant PL intensity decrease with time, attaining 75 and 60 relative units for wafers of both types. The irradiation doze PC and PL dependences in the 10(na16)….5x10(na17) cm(na-2) range were determined. Due to these effects it turns possible to control the properties of these semiconductors and to correlate them with the creation of radioactive defects and their influence on the model of the recombination process energy diagram. The possible mechanisms of the investigated process are discussed.

irradiation of semiconductors; recombination; photo-luminescence; photoconductivity

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