US Patent 7368759 Semiconductor light-emitting device

A semiconductor light emitting device has a light-emitting portion formed on a semiconductor substrate, an As-based p-type contact layer formed thereon, a current spreading layer formed thereon of a metal oxide material, and a buffer layer formed between the p-type cladding layer and the p-type contact layer. The buffer layer has a group III/V semiconductor with a p-type conductivity and hydrogen or carbon included intentionally or unavoidably therein, and the buffer layer has a thickness equal to or greater than a diffusion length L of a dopant doped into the p-type contact layer.