The ZnO/MgO Quantum Wells Were Prepared By Magnetron Sputtering And Their Optical Properties Were Studied

With band gap of about 3.37eV and exciton binding energy of about 60meV, ZnO is a typical wide band gap semiconductor of ?-? class. For it's exciton binding energy is far above room temperature thermal energy (about 26meV), so it can realize exciton stimulated radiation at room temperature or even higher temperature. Besides, the crystal structure and photoelectronic property of ZnO is similar with GaN which is a typical third generation semiconductor. In addition the preparation of ZnO is more simple, the raw materials are richer and it has no pollution for the environment, so ZnO has a broad application prospect in the field of photoelectric devices. But the preparation of stable p-type ZnO with low resistivity is a problem that has not been solved and this problem hinders ZnO research progress and application on photoelectric devices. Thus, preparating heterojunction, quantum wells or superlattice by using ZnO and other materials become a focus of research. With the band gap of about 7.78eV, MgO have good restricton effect on carriers in ZnO/MgO quantum wells. In addition, MgO has good properties of chemical stability, thcrmostability and etc. This paper reports the preparation of ZnO/MgO quantum wells on Si which is easy to integrate with semiconductor process by magnetron sputtering method and researches its optical performance. This paper mainly contents three parts.The frist part optimizes four experimental factors:working pressure, sputtering power, substrate temperature, argon oxygen flow rate ratio of the preparation of ZnO by magnetron sputtering method with single factor method step by step. Combined with XRD, film thickness, SEM test results we analyse the effect of the four factors on ZnO films. It rurns to be that the four factors produce grect effect on the quality of crystallization of ZnO films and working pressure and sputtering power have greater impact on film depositon rate, however substrate temperature has greater influence on the preferred orientation of ZnO.The second part optimizes three experimental factors:argon oxygen flow rate ratio, substrate temperature, working pressure of the preparation of MgO. According to XRD, film thickness, SEM test results we get the conclusion that the three factor exert an influence on the quality of crystallization and deposition rate of MgO, what's more, argon oxygen flow rate ratio is a key factor of determining the preferred orientation of MgO.The third part prepares ZnO/MgO silgle quantum wells and cycle of 5 quantum wells with tap layer width of 2,4,6,8nm by using the optimized experimental parameters of ZnO and MgO and research the photoluminescence of these quantum wells at room temperature. PL spectrums and Gaussian fitting results show that exaction emitting peaks occur blue shift or red shift for the effect of quantum confined (QC) effect or quantum confined stark (QCS) effect and the peaks in the visible light range are caused by defacts in ZnO. The analysis of the light-emitting mechanism is based on the results in literature.Test results of atomic force microscope (AFM) show that the root mean square roughness of surface of ZnO/MgO single quantum well with L_w of 6nm is 1.462nm and that of ZnO/MgO multi quantum well with L_w of 4nm is 1.822nm.