Identification of the IB Emission Band in Al-Doped ZnS Crystals
N.Q. Liem, V.X. Quang and D.X. Thanh
Institute of Material Science, Nghia do-Tu liem, Hanoi, Vietnam
Received: February 19, 1996; in final form: May 21, 1996
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Time-resolved luminescence spectroscopy and thermal lensing techniques are applied to the study of deep centre photoluminescence and absorption in Al-doped ZnS crystals, which are as-grown or heat treated in different Zn rich or S rich atmospheres. A blue emission band peaking at 2.89 eV has been identified as IB band in all the mentioned crystals. Parameters of the IB band at 300 K, 77 K and 10 K such as peak energy, half width of spectrum, radiative lifetime have been determined. The IB band exhibits some special properties such as a shift neither with increasing delay time nor with excitation intensity nor with sample temperatures as well as a superlinearly excitation intensity dependence of the luminescence. An energy diagram and electronic transitions in the IB centre are presented to explain the experimental results.
DOI: 10.12693/APhysPolA.89.717
PACS numbers: 78.55.-m, 78.55.Et