Patent ID: 8124989

Claim:
An optoelectronic device with an epi-stacked structure, comprising: a substrate; a buffer layer formed on said substrate, said buffer layer comprising at least: a first nitride based compound layer on said substrate; a II/V group compound layer on said first nitride-containing compound layer; a second nitride-containing compound layer on said II/V group compound layer; and a third nitride-containing compound layer on said second nitride-containing compound layer; and an epi-stacked structure formed on said buffer layer, wherein said epi-stacked structure comprises: a first semiconductor conductive layer formed on said buffer layer; a multi-layer structure with an average energy gap (Eg (avg,SRS) ) formed on said first semiconductor conductive layer, the multi-layer structure comprising: a first semiconductor structure with an energy gap Eg 1 having a thickness t 1 ; a second semiconductor structure with an energy gap Eg 2 having a thickness t 2 ; and a third semiconductor structure with an energy gap Eg 3 sequentially stacked and having a thickness t 3 ; wherein said average energy gap of the multi-layer structure satisfies E ⁢ ⁢ g ⁡ ( avg , S ⁢ ⁢ R ⁢ ⁢ S ) = ( t 1 ⁢ E ⁢ ⁢ g 1 + t 2 ⁢ E ⁢ ⁢ g 2 + t 3 ⁢ E ⁢ ⁢ g 3 ) t 1 + t 2 + t 3 ; an active layer with an energy gap (Eg ,active ) formed on said multi-layer structure wherein said energy gap (Eg ,active ) of said active layer is different from said average energy gap (Eg (avg,SRS) ) of said multi-layer structure; and a second semiconductor conductive layer formed on said active layer.