Scanning confocal microscopy is used to study blueemitting Indium Gallium Nitride (InGaN)/Gallium Nitride (GaN) multi-quantum wells grown by metal-organic chemical vapor deposition under different growth conditions. Sub-micrometer scale spatial and spectral variation of photoluminescence (PL) has been observed. Spectrum measurement shows the PL peak in bright region is red-shifted comparing with that in dark region, and that the peak intensity of bright region is at least twice as strong as that of dark region. Images show defect luminescence features which are about 500 nm in diameter and have PL peak at around 550 nm. Experiments show that reducing In/Ga ratio, increasing growth pressure and increasing NH 3 flow rate can all increase the localization effect and result in the increase of sample average PL intensity. Moreover, average PL intensity increases with the increasing of bandgap difference and PL peak intensity difference between bright and dark regions in PL.

As compound semiconductors continue to make inroads into common electronic devices, it is critically important to lower the cost of the primary metal-organic chemical vapor deposition (MOCVD) epitaxial process, which creates the foundation for the devices. Both GaN-based light-emitting diode (LED) and AsP-based concentrator photovoltaic (CPV) markets have been focused on simultaneous cost-reduction, cycle time reductions, and device efficiency improvements, which can be realized utilizing higher growth rates and operating pressures. To achieve these goals, it has become increasingly important to understand the underlying growth mechanisms that drive the chemistry within the MOCVD process.Higher growth rates and higher operating pressures both result in parasitic gas-phase particle formation, which degrades the physical, electrical and optical properties of the deposited layers. In extreme cases, it can reduce the deposition efficiency to the point where increasing the reactant constituents results in reduced growth rates. In this paper, we will examine the tradeoffs that need to be made to achieve good crystal quality with abrupt interfaces, smooth surface morphology, and good minority carrier properties for films deposited at high growth rates and high pressure. While exceptional device performance has been achieved for both GaN-based LEDs and AsP-based CPV cells, it is primarily cost that is limiting full-scale adoption of compound semiconductors into these potentially enormous markets.