Investigation of deep centres of chlorine-doped zinc sulfide crystals

Abstract

Deep centres of the ZnS: C1 single crystals are investigated by the method of impurity electroabsorption (IEA) and photoconductivity (PhC). I n accordance with estimations fulfilled a number of the levels obtained are ascribed to Vin; (VznCls)' and Vin and also t o (VznGazn)', whose energy levels are obtained in a previous paper. In the induced IEA spectrum two fixed peaks are found whose satellite displacements A are described by different dependences on the modulating voltage U, namely A -U1/3 and -U W . This is apparently caused by the nature of centres responsible for the observed structures in the IEA spectra.B pa6o~e HCCJXeAyIOTCH rnyboKEIey pOBHX B MOHOKpMCTaJIJIaX ZnS: c1 MeTOAaMH IIpEIMeCHOrO 3JIeKTpOIIOrJlOIUeHHFi (n3n) EI @OTOIIpOBOAUMOCTH (Qn). no PeayJIb-TaTaM H3MePeHFln OIIpeneJleH 3HepreTMqeCKHfi CneKTp rny60mx ypofjaefi. COrJlaC-HO IIpOBeneHHbIM OUeHKaM, pfin IIOJlyWHHhIX YpOBHefi npMnHCaH Vzn; (VznCls)' EI viu, a TaKWe (VznGazn)', 3HepreTWfeCHH8 YpOBeHb KOTOpOrO nOJlyseH B IIpeAbIny-Uefi pa6ol.e. B CneKTpe IIHLfYUApOBaHHOrO n3n 0 6~a p y w e~b 1 ABa HeIIOABHHWbIX IIEIKB, CMeweHHFi CaTeJIJIHTOB KOTOPbIX A OIIHCbIBaIOTCFi pa3HbIMH 3aBBEICHMOCTIIMA 06yCJXOBJXeHO IIpHpOLfOfi qeHTPOB, OTBeTCTBeHBbIX 38 Ha6~1KmaeMbIe OCO6eHHOCTH OT MoRynHpyIowero Hanpmmmsr, a xiMeHHo A -Ull3 EI -U213, TO, IIO-BK~WOMY, B cnempax n3n.

Influence of Random Electric Fields on the Polarization of Deep Centre Electroabsorption

“…The 2.8 eV peak, which appears in the IEA spectrum of "pure" ZnS only, and which was observed earlier [7], we have attributed to Vin as in [7].…”

“…I n [6] in which ZnS : Ga single crystals were investigated, the 3.18 eV peak was ascribed by us to the (VznGaZn)' complex, in which VP, and gallium are separated by the nearestneighbour distance. Analogous complexes were considered also in [7]. If one assumes that doping with indium is similar to doping with Ga and C1 and leads with great probability to the formation of complexes consisting of Vin and an impurity atom at the nearest-neighbour distance, i.e.…”

Influence of the presence of a fluxing agent and its composition on the spectral characteristics of ZnS(Cu) obtained by self-propagating high-temperature synthesis

“…To date, the nature of the luminescence centers, causing the blue and green bands of Cu in ZnS, is well studied [8][9][10][11][12][13]. In the works [11][12][13][14][15], it is shown that the center of the green glow of copper with λ max ~ 505…535 nm is isolated copper ion, replacing zinc ion in the ZnS lattice. The blue band with λ max ~ 450…465 nm is related to formation of associates like to the close DA-pair Cu i -Cu Zn [16].…”

“…Possibly, the presence of a fluxing agent leads to increasing the partial pressure of Cl [17], which increases the solubility of copper in the basis of luminophore and results in additional association of copper ions and formation of centers like to the close DA-pair Cu i -Cu Zn and, accordingly, to combusting of PL blue band. Effect of Cl, as a co-activator, on the spectral composition and PL intensity is related with necessity to compensate charge of internal defects in material, which is in sufficiently details described in the works [8][9][10][11][12][13][14]. In [14], it has shown that even a small amount of the Cl impurity in ZnS conduces introduction of copper into the sites of Zn sublattice, or filling the Zn vacancies, which leads to an increase in contribution of the green band to luminescence.…”

“…Effect of Cl, as a co-activator, on the spectral composition and PL intensity is related with necessity to compensate charge of internal defects in material, which is in sufficiently details described in the works [8][9][10][11][12][13][14]. In [14], it has shown that even a small amount of the Cl impurity in ZnS conduces introduction of copper into the sites of Zn sublattice, or filling the Zn vacancies, which leads to an increase in contribution of the green band to luminescence. The appearance of the blue band in the PL spectrum, when introducing Cl, is obviously associated with the formation type of the centers similar to close DA-pair Cu i -Cu Zn .…”