As society has become very sensitive to the need for both energy-efficient information technology devices and energy-efficient and environmentally aware manufacturing processes the important communications technology sector is not unaffected. Wireless handset and optical communications manufacturers look for ways to adopt greener manufacturing practices while also continuing to improve the performance and cost of their systems. Fundamental to all of these communications technologies are the electronic and optoelectronic devices and the compound semiconductor materials from which they are made. The goal of this research is to develop improved and higher performance components for both wireless and optical communication systems by utilizing a newly discovered oxygen-enhanced wet thermal oxidation process for growing high quality insulating oxide layers on the GaAs and InGaAs from which many of these devices are made. The Intellectual Merit of this effort lies in the further exploration and application of these oxides to real world devices. The optimum conditions or growth of such oxides will be investigated, with a focus on improving reproducible uniformity and reducing interface defect density. GaAs oxides will be explored for use as a field oxide for GaAs integrated circuits to improve current isolation between individual devices over current isolation methods. InGaAs native oxides will be applied to InGaAs p-i-n photodiodes, which are ubiquitous in optical fiber communication systems, and studied for their potential to reduce surface states and associated dark current, both of which significantly reduce device performance. The research is potentially transformative by nature of its promise for realizing powerfully useful new insulating and passivating dielectric materials capable of impacting a wide range of electronic and optoelectronic devices while at the same time being elegantly simple and, with very low environmental impact, compatible with the green manufacturing movement. The Broader Impact of this work will be found in the expected improvements in the technical performance of both wireless and optical fiber communications systems, improvements that will come with significant reductions in component manufacturing and/or final integrated system cost. Improvements in GaAs integrated circuits used in wireless handsets may reduce power consumption by reducing leakage currents between transistor devices, enabling longer battery life. Improvements in the sensitivity of photodiodes will enable lower cost fiber communication systems to increase the adoption of broadband optical communications in underserved areas. Bringing fiber closer to the home, schools and medical offices will accelerate the development and adoption of bandwidth-intensive applications such as digital video, video conferencing, and internet communications across multiple platforms (from computers and televisions to wireless base stations to mobile handsets). Secondary impacts include advancing discovery and understanding through the further development of III-V compound semiconductor oxidation technology, with other possible applications such as improved photovoltaic devices.