RADICAL BEAM GETTERING EPITAXY OF ZNO AND GAN

P-type ZnO layers with a hole mobility about 23 cm²/(V s), and a hole concentration about 10¹⁵ cm^-3 were grown by means of radical-beam gettering epitaxy (the annealing of n-ZnO single crystals in atomic oxygen flux). The effect of native defects on the photoluminescence spectra of the layers was studied. The dominant bands in the spectra peaked at 370.2 and 400 nm. These bands were attributed to the annihilation of exciton localised on neutral V_zn and to electron transitions from the conduction band to singly positively charged V_zn correspondingly. The effect of annealing in atomic nitrogen flux of p-CaN:Mg films on their photoluminescence spectra and on the value of their conductivity were studied. Such annealing leads to appearance of a number of emission bands that peaked at 404.9, 390.8 and 378.9 nm and increases hole concentration from 5 × 10¹⁵ to 5 × 10¹⁶ cm^-3, and the hole mobility from 120 to 150 cm²/(V s). The n-ZnO – p-GaN:Mg electroluminescence heterostructures were obtained. Their spectrum contains bands in the excitonic region of GaN at the wavelength 360.2 nm and in the edge region at wavelengths 378.9 and 390.8 nm.