ZnO Nanoflake-Decorated Si Nanowire Photodiode with Enhanced Reponsivity

We report a Si nanowire photodiode decorated with ZnO nanoflakes for enhanced photoresponse. The photodiode consists of a core-shell Si nanowire array and ZnO nanoflakes and exhibits a higher responsivity than the Si nanowire photodiode. The improvement is achieved by decorating the nanowire array with ZnO nanoflakes. In addition, the responsivity increases slightly with applied reverse bias. Analysis of the reflectance and energy band diagram was performed in order to elucidate the enhancement mechanism. The higher responsivity is caused by reduced surface reflectance, which allows absorption of more light within the Si nanowire array.