The solvothermal synthesis of III-V nitride and II-VI oxide semiconductors

A crucial step in the metamorphosis from an age of industry to an age of information was and is the development of the semiconductor diode laser. This technology has found applications in telecommunications, data storage, and document production. Currently, the search is on for a material that will extend diode lasers from the near-infrared and red wavelengths to the blue and near-ultraviolet regions. Both the III-V nitrides and the II-VI oxides possess the desired properties for semiconductor device applications in both the blue and ultraviolet wavelengths. However, the synthesis of bulk crystals of these materials is extraordinarily difficult, and the thermodynamic properties of these materials make any standard method of melt or sublimation growth very problematic.; It is well known that good quality single crystals of α-quartz can be prepared in supercritical water and that quartz crystals as large as one kilogram can be grown in under 30 days. The success of this technique has made the use of supercritical fluids a very attractive synthetic medium, and it is proposed that this same method can be applied to the nitrides using supercritical ammonia and to the oxides using supercritical water. This research project will investigate the critical parameters involved in the bulk crystal growth of these materials. These parameters include PvT relationships, mineralizer and solubility studies, conditions for spontaneous nucleation, baffle design and substrates for transport growth. It is the goal of this research to develop solvothermal systems for the growth of high quality, centimeter-size, single crystals of gallium nitride (GaN) and zinc oxide (ZnO).