Surface Plasmons Enhanced Light Emission From ZnMgO Films And ZnO/ZnMgO SQW

For realizing the application of ZnO-based optoelectronic devices, it is important to prepare high-quality ZnMgO and ZnO/ZnMgO quantum well and improve the luminescence efficiency. Recently, surface plasmons (SPs) have been utilized to enhance the light emission efficiency of semiconductor materials and devices. In this thesis, we concentrated on studying the photoluminescence properties of ZnMgO films and ZnO/ZnMgO single quantum well (SQW) and enhancing the ultraviolet light emitting by SPs coupling. The primary results are described in the following:(1) ZnO/ZnMgO SQW with different well layer thickness was prepared by pulsed laser deposition and the quantum confinement effects were observed. The emission energy dependence of the well layer thickness was calculated by a theoretical model, and the result was agreement with experimental data. Pleated ZnO nanosheets were prepared by metal organic chemical vapor deposition and negative thermal quenching of both the excitonic and green emissions was observed. Based on the model of multi-level transitions, the energy level of surface traps could be extracted, which was 81meV below the conduction band minimum.(2) Metal films were prepared by electron beam evaporation. Using the reverse micellar methods, the Al and Pt nanoparticles have been fabricated. The surface morphology and optical absorption properties have been studied. Al micron- patterns have been fabricated by the standard photolithography.(3) By capping Al on the surface of ZnMgO films, the enhancement of ultraviolet emission has been observed, which can be interpreted in terms of surface plasmon coupling. The influences of the metal thickness and annealing condition on the enhancement effect have been studied. When the metal thickness was 2nm,3.5 folds band edge emission enhancement has been achieved. After annealing, the metal film transformed to nanoparticles. Due to the energy matching and scattering effects, stronger enhancement effect has been achieved (4.7 folds).(4) The Al/Ag bi-layer nanoparticles have been used to enhance the light emission from ZnO/ZnMgO single quantum well. By the surface plasmon coupling, a three folds enhancement of spontaneous emission from well layer and a six folds enhancement of the emission from barrier layer were obtained.