THERMALLY STIMULATED CHARGE AND LIGHT EMISSIONS FROM UNIRRADIATED LINBO3 SINGLE-CRYSTALS AND OPTICAL-SPECTRA OF THE LIGHT

Thermally stimulated charge emission (TSCE) and thermally stimulated light emission (TSLE) from poled and unirradiated single crystals of LiNbO3 are recorded simultaneously, when the crystal temperature is varied continuously between 80 and 600 K in vacuum (almost-equal-to 10(-5) Pa). The TSCE shows sudden changes in intensity coinciding with the TSLE which consists of a series of light pules, so that the TSCE glow curve has many discontinuous points. The peak temperature and intensity of the TSCE, and also the intensity and occurrence of the TSLE depend upon the orientation of the crystal face and the direction of the temperature gradient in the crystal. Most of the light pulses have very short durations and have line-like spectra, the wavelengths of which differ from each other irregularly pulse by pulse, independent of the above conditions and are distributed over the range measured, 200 to 800 nm. Field electron emission and charge carrier recombination may cause most of the TSCE and TSLE, respectively.