Photoluminescence properties of thin nitrogen- and phosphorus-doped ZnO films fabricated using pulsed laser deposition

摘要

The production of n- and p-type high-quality film structures is a foreground task in tackling the problem of growing the light-emitting p-n junctions based on zinc oxide. The ZnO:N and ZnO:P thin-film samples are produced from ceramic targets using the pulsed laser deposition. Zn _3N _2, MgO, and Zn _3P _2 are introduced in the ZnO ceramic targets for the fabrication of the p-type ZnO films. Gases O _2 and N _2O are used as buffer gases. The thermal annealing of the ZnO films is employed. The resistance and photoluminescence (PL) spectra of the ZnO films are measured prior to and after annealing. The dependence of the ZnO PL peak amplitude and position prior to and after annealing on the level of doping with nitrogen and phosphorus is established. The PL characteristics of the films are studied at cw optical excitation using a He-Cd laser with a radiation wavelength of 325 nm. The PL spectra in the interval 300-700 nm are recorded by an HR4000 Ocean Optics spectrometer in the temperature range 10-400 K. The effect of the conditions for the film deposition on the PL spectra is analyzed. The effect of the N- and P-doping level of the ZnO films on the PL intensity of the films and the position of the PL bands in the UV region is investigated. The short-wavelength (250-400 nm) transmission spectra of the ZnO:P films are measured. The effect of the P-doping level on the band gap of the ZnO films is studied.