Investigation On Ga-N Codoped P-ZnMgO Films

Zinc oxide (ZnO) is a direct wide band-gapâ…¡-â…¥compound semiconductor material with E_g of 3.37 eV at room temperature and exciton binding energy of up to 60 meV at room temperature The bandgap of ZnMgO could be modulated during 3.3-7.8 eV due to the incorporation of Mg element and it has promising applications in the fields of ultraviolet (UV) light electrical devices. ZnMgO could heighten the luminous efficiency clearly for application in ZnMgO/ZnO heterojunction, superlattice, and quantum well structure. Therefor, the research on ZnMgO film is very important and valuable. Unfortunately, there are few reports on ZnMgO film, especially on codoped ZnMgO film.In this paper, Ga-N codoped ZnMgO films were deposited on glass substrates by direct current reactive magnetron sputtering and the effect of Mg content, Ar/N₂O, and O₂/(NH₃+O₂) on ZnMgO films were investigated. The main work is as follows:1. The Ga-N codoped ZnMgO films with different Mg content were grown on glass substrates with N₂O as N source and O source. The results of measurement showed that the diffraction angles (20) increased monotonously and the length of c-axis increase with increasing Mg content. With the incorporation of Mg, the absorption edge shifts to the shorter wavelength side compared to pure ZnO films. All the films show definitive p-type conductivity, regardless of the Mg composition. The ZnMgO:(Ga,N)/ZnMgO:(Ga) homojunction exhibites a clear rectifying behavior.2. The p-type Ga-N codoped ZnMgO films were grown on glass substrates with N₂O as N source and the effect of Ar/N₂O ratio on the p-type Ga-N codoped ZnMgO films was investigated. The optimized electrical properties were achieved when the ratio of Ar/N₂O is 3/2. The ratio of Ar/N₂O has little effect on the bandgap of ZnMgO films.3. The Ga-N codoped ZnMgO films were deposited on glass substrates with NH3 as N source and the effect of O₂/(NH₃+O₂) ratio on the Ga-N codoped ZnMgO films was investigated. The optimized electrical properties with the resistivity of 31.65Ωcm, the hole concentration of 1.27×10¹⁷ cm^-3 and the mobility of 1.56 m²/Vs was achieved when the ratio of O₂/(NH₃+O₂) is 60%.