Study On MOCVD Growth Of ZnO Films And Proterties Of GaN/Si Green LEDs

This dissertation includes two parts. The first part is dedicated to the study of the MOCVD growth and the properties of ZnO films. The second part is a investigation of the fabrication and the properties of GaN/Si green LEDs.Part I:As a versatile material, ZnO has been used for decades for many applications. In recent years, there is a renewed interest towards ZnO for short wavelength light emission applications due to the fast growing market for short wavelength light emitting devices. Unlike the traditional applications, singlecrystal ZnO is required for fabrication of light emitting devices. Though massive progress in growth of high-quality ZnO films has been made in recent years, however, applicable ZnO light emitting devices have not been fabricated yet. The first object of the dissertation is to grow device-quality ZnO films and so that pave the way for high performance ZnO light emitting devices.The film growths were performed using a home made atmospheric pressure MOCVD system. Influence of various growth parameters on the film properties was studied and high quality ZnO films were prepared on both sapphire and silicon substrates by optimizing the growth conditions. For the ZnO films grown on sapphire substrates, a systematical investigation on the structural and optical properties was conducted. And the influence of high temperature annealing on the properties of these films was studied. Some encouraging results are found in these studies and they are followed as:1. A high temperature buffer layer growth method was proposed. By this method, high quality ZnO films with the (0002) and (1012) XRD rocking curve FWHM of 112 arcsec and 214 arcsec, respectively, were prepared on sapphire substrates. These values are the lowest ones so far reported for ZnO films grown by MOCVD.2. By using a A1N buffer layer, high quality ZnO films were grown on Si(111) substrates. The minimum FWHM for (0002) and (1012) XRD rocking curves of these films were 410 arcsec and 1321 arcsec, respectively. These results are the best for...