DIRECT LUMINESCENCE AND THERMALLY STIMULATED LUMINESCENCE OF 4H CdI2

Direct luminescence (DL) spectra of 4H Cd12 in the spectral region 1.8-3.4 eV at temperatures between 9.3 and 215 K and thermally stimulated luminescence (TSL) spectra are reported. The DL spectra consist of several overlapping broad emission bands. These bands are due to radiative recombination of localized (trapped) electrons with localized (trapped) holes. With a simple theory, which takes into account the electrostatic interaction between electron and hole it was possible to explain the position of the observed emission bands quantitatively. The TSL spectra show emission bands at several temperatures. These bands are due to the recombination of initially trapped charge carriers. The trap depths can be calculated, by taking into account the electrostatic interaction between the trapped charge carriers.