Doping the thin films by using the original Close Space Sublimation method

Abstract

The review is devoted to the results of studies on the structure, morphology, optical, and luminescent properties of thin films doped with the modified Close Space Sublimation method. Using this method, ZnO and ZnS films were doped with impurities of various metals – Ag, Cu, Ga. It has been shown that doping the films leads to an improvement in the crystal structure and radiative properties of the films. When using doping with this method, cathodoluminescent screens with high luminance have been manufactured. The screens show a deeper green color than C1 and C2 commercial phosphors. The luminance values at 300 K are 200 cd/m² for the ZnS〈Cu,Ga〉 film and 1100 cd/m² for the ZnO〈Cu,Ga〉 ones. At 77 K, the cathodoluminescence luminance for ZnO〈Cu,Ga〉 film is 3700 cd/m² and has not reached the limit value. Doping the ZnO with copper has greatly improved the crystal structure and made it possible to obtain films with white-light emission. Ag doping suppresses the wide visible bands of the photoluminescence spectra. The intensity of the ultraviolet band is 15-fold increased as compared to their reference non-doped films. The ultraviolet/visible emission ratio reached 20.