Patent ID: 6861681

Claim:
An on-p-GaAs substrate Zn 1-x Mg x S y Se 1-y pin photodiode comprising: a p-GaAs single crystal substrate having a top surface and a bottom surface; a p-(ZnSe/ZnTe) m (m: integer denoting a number of pair layers) superlattice which is made by piling p-ZnSe thin films and p-ZnTe thin films reciprocally for changing bandgaps stepwise and is epitaxially grown directly on the top surface of the p-GaAs substrate; a p-Zn 1-x Mg x S y Se 1-y (0≦x≦0.8, 0≦y≦0.8) layer epitaxially grown on the p-(ZnSe/ZnTe) m superlattice; an i-Zn 1-x Mg x S y Se 1-y (0≦x≦0.8, 0≦y≦0.8) layer epitaxially grown on the p-Zn 1-x Mg x S y Se 1-y layer; an n-Zn 1-x Mg x S y Se 1-y (0≦x≦0.8, 0≦y≦0.8) layer epitaxially grown on the i-Zn 1-x Mg x S y Se 1-y layer; a metallic n-electrode which is formed upon a part of the n-Zn 1-x Mg x S y Se 1-y layer and has a top aperture for allowing incidence light to enter; and a metallic p-electrode formed on the bottom surface of the p-GaAs substrate.