Optical And Electrical Properties Of ZnO Single Crystal Films&Heterojunction Structures Grown By Laser Molecular Beam Epitaxy

As the representative of II-VI group wide band gap semiconductor materials, ZnO has aseries of optical and electrical properties. Research about ZnO has became hot spots in thevisible and ultraviolet optoelectronic field. Since high-quality of epitaxial ZnO thin films isthe basis for the preparation of high performance optoelectronic devices, improving thequality of the ZnO thin films has always been the focus of ZnO materials researches. In thispaper, we attempted to prepare ZnO film by laser molecular beam epitaxy (LMBE) techniquesand explored the high-mobility heterojunction films of ZnO/MgZnO:Ga. And the electrical,optical and structural properties have been studied. The main contents are as follows:(1)The effects of oxygen partial pressure, substrate temperature and laser power densityon the quality of ZnO thin films had been studied. The films have been grown on c-sapphiresubstrates with the oxygen pressure in the range of5×10-3Pa~1.8×10-2Pa, the substratetemperature in the range of500℃~700℃, and the laser power density in the range of8×103mJ/cm2~15×103mJ/cm2. All the films had been characterized by X-ray diffraction, absorptionspectroscopy, photoluminescence spectroscopy and electrical properties test of the Hall. Afterthat, the optimized growth conditions were obtained.(2)We designed ZnO/MgZnO:Ga heterojunction based on the band theory, andhigh-quality of epitaxial ZnO thin films. The heterojunction film and the single-layer film onthe optical properties and electrical properties had been analyzed and compared.The resultshows that the electron mobility of heterojunction film has been improved, which verified thatthe two-dimensional electron gas had formed at the interface of ZnO and MgZnO:Ga films. Itlays a good experimental foundation for the future researches.