3-5 Group compound semiconductor and semiconductor device

A 3-5 group compound semiconductor comprising a conductive substrate and a device layer of a 3-5 group compound semiconductor formed by epitaxial growth on said conductive substrate, which comprises an oxygen-doped AlGaAs layer between said conductive substrate and said device layer.

An element array comprising a conductive substrate and a device layer of a 3-5 group compound semiconductor formed by epitaxial growth on said conductive substrate, said device layer being a double hetero type device layer comprising a pair of hetero barrier layers and an active layer held between said hetero barrier layers, wherein the conduction type of that hetero barrier layer which, of said pair of hetero barrier layers, is provided on the conductive substrate side (hereinafter referred to as the lower hetero barrier layer) is the same as that of said active layer.