Growth and optical properties of InxAlyGa1-x-yN quaternary alloys

InxAlyGa1-xN quaternary alloys with different In and Al compositions were g rown by metalorganic chemical vapor deposition. Optical properties of these quaternary alloys were studied by picosecond time-resolved photoluminescen ce. It was observed that the dominant optical transition at low temperature s in InxAlyGa1-xN quaternary alloys was due to localized exciton recombinat ion, while the localization effects in InxAlyGa1-xN quaternary alloys were combined from those of InGaN and AlGaN ternary alloys with comparable In an d Al compositions. Our studies have revealed that InxAlyGa1-xN quaternary a lloys with lattice matched with GaN epilayers (y approximate to4.8x) have t he highest optical quality. More importantly, we can achieve not only highe r emission energies but also higher emission intensity (or quantum efficien cy) in InxAlyGa1-x-yN quaternary alloys than that of GaN. The quantum effic iency of InxAlyGa1-xN quaternary alloys was also enhanced significantly ove r AlGaN alloys with a comparable Al content. These results strongly suggest ed that InxAlyGa1-x-yN quaternary alloys open an avenue for the fabrication of many optoelectronic devices such as high efficient light emitters and d etectors, particularly in the ultraviolet region. (C) 2001 American Institu te of Physics.