Temperature behaviour of the photoluminescence spectra of polycrystalline ZnSe films with different surface treatment

Abstract

We present the photoluminescence spectra obtained in the case of normal incidence of exciting radiation at both polished and unpolished surfaces of chemicalvapour deposited ZnSe films in the temperature range 12-300 K. The luminescence has been excited using either a continuous-wave He-Cd laser with the wavelength λ ex = 325 nm (i.e., under the condition hv ex > E g for the photon energy) or a semiconductor laser with λ ex = 532 nm (i.e., hv ex < E g). We show that the temperature dependences of intensity, spectral position and half-width of a green photoluminescence band detected in the both alternative cases are very different in the region 12-80 K. However, their behaviours become very close to each other when the temperature increases up to 180 K. Finally, the above spectral parameters are almost the same in the region 180-300 K.

Temperature Behaviour of the EPR Spectrum of Polycrystalline ZnSe

“…In recent years, the role of oxygen and the influence of the sample surface on the optical properties of A II B VI crystals, including the luminescence processes observed in these materials, have been intensively studied [1][2][3][4][5][6][7][8][9][10]. This is because the long-wavelength emission bands observed in these crystals are impurity-defect luminescence spectra, the study of the properties of which is necessary for modern optoelectronics operating in the blue-green and red regions of the spectrum [1,4].…”

“…[6][7][8][9][10], where photoluminescence has been studied from a polished and unpolished sample surface (in both cases, in the same sample, there is the same excitation); some difference has been observed in the spectra, and it was considered that this difference is due to the uneven distribution of background impurities (they can be called uncontrolled impurities) over the depths of the sample. The temperature behaviour of the intensity of the green band under UV excitation (325 nm), observed from the polished and unpolished sample surfaces in the temperature range of 80-180 K, is different, and a similar behaviour has been observed upon excitation by x-rays, where the quantum energy is of 12 keV [6,8]. The authors of Refs.…”