The Preparation Of Zn_1-xMg_xO Alloy On Silicon Substrate By Pulsed Laser Deposition And Properties Characterization

ZnO showed large potentiality to be applied to optoelectronic devices, wich leads to the research work on ZnMgO semiconductor alloy. By varying the Mg composition, the band gap energy of ZnMgO alloy can be tuned.In recent reports, ZnMgO alloy were synthesized on sapphire or ScAlMgO4. For the first time, ZnMgO alloy were synthesized on silicon by pulsed laser depostion (PLD) in this paper. Si substrate will facilitate the device process. In our experiments, ZnO> Zno.gMgo.2O> Zn0.63Mgo.3?0> Zno.5gMgo.42 were used as targets, and 20 ZnMgO samples were grown at five different substrates temperatures, 500癈\ 550癈\ 600癈> 650癈\ 700癈. Our work is as below:1. For the first time ZnMgO alloy were synthesized on silicon by pulsed laser depostion (PLD)2. PLD was employed to prepare ZnMgO alloy for the first time in China.3. The effect of substrate temperature on the quality and optical properties of ZnMgO alloy, which was rarely studied, was discussed. With the increasing of substrate temperature, the Mg composition increased, leading to the increasing of band gap energy of ZnMgO alloy. The optimized substrate temperature is 650癈. The ZnMgO alloy deposited at 650癈 was of C-axis orientation and high crystalline quality. In XRD spectrum, Only (002) peak was observed and the full width at half maximum (FWHM) was only 0.19? The lattice constant mismatch between ZnMgO alloy and ZnO was only 0.5%. These results are better than some other results.4. PL measurement was carried out at room temperature. The UV emission peaks of ZnMgO alloy have blue shifts from that of ZnO. It indicated the band gap energy of ZnMgO thin films have been tuned by alloying with MgO. The ratio (R) of near band energy to defect level peak intensity was as large as 159, which was higher than other results.5. The effect of Mg compostion in targets on crystalline quality of ZnMgO alloy was studied. The ZnMgO alloy was single phase when Mg composition of target wasbelow 37%, and when it was beyond 37%, phase separation was observed. The FWHM of (002) peak increased with the increasing of Mg composition in targets. 6. ZnMgO alloy were annealed in Oxygen and Nitrogen at 500C for Ih. The annealing effects on the ZnMgO alloy were explored.