Solar cell technology has long relied upon Si and GaAs based materials. While this industry is mature, it has approached a plateau in the push to increase efficiency. It has been proposed that the InGaN ternary materials system is ideal for this purpose. In this work we report on the growth, fabrication and testing of photovoltaic properties of InGaN based solar cells grown via metalorganic chemical vapor deposition (MOCVD). In order for solar cells to work effectively, a minimum active region thickness is necessary for sufficient absorption of photons for conversion. At low In content compositions, high quality material has been grown and a simple p-i-n type solar cell with a single absorbing layer can be produced. However, at high In content compositions critical thickness limits for the thin films are well below the thickness requirements for full absorption. High In compositions are necessary to efficiently match the solar spectrum when designing multijunction solar cells. Solar cells require a thickness of 100-200 nm for sufficient absorption.

Growth optimization and results for p-i-n type: single double heterostructures, multiple double heterostructure (MDH), and MQW, solar cells will be reported for InGaN grown on sapphire in the +c [0001] orientation as well as InGaN grown on bulk m-plane (10-10) substrates. Non-polar oriented growth of InGaN was investigated since as In content increases in typical c-plane growth, the polarization fields in the double heterostructure design of the p-i-n solar cell oppose the built in field of the junction and could potentially hinder carrier collection. At low In content, m-plane InGaN solar cells outperform c-plane solar cells with the same composition due to the higher quality material grown homoepitaxially on bulk GaN substrates.