New developments in III-Nitride material and device applications

An overview of our recent progress in the development of the III-Nitrides is presented. Improvements in the basic material quality are reported along with the demonstration of devices based on this material. GaN films grown by low pressure metallorganic chemical vapor deposition using trimethylgallium and triethylgallium as gallium precursors are compared. GaN layers grown using triethylgallium exhibited superior electrical and optical properties and a lower carbon impurity concentration. GaN thin films were doped during metallorganic chemical vapor deposition with sulfur using dilute hydrogen sulfide in hydrogen. The low resultant carrier concentrations indicate that sulfur has a limited solubility in GaN. GaN/InGaN/GaN double heterostructures were deposited: one with a silicon doped InGaN layer and the other with a magnesium doped InGaN layer. The electroluminescence spectrum is shifted to longer wavelengths in the structure with the magnesium doped InGaN layer. An additional red peak is seen in the electroluminescence spectrum of the magnesium doped structure. We believe this peak may be due to a transition metal (i.e. Cr) which absorbs in the green and emits in the red.