Multipeak Emissions and Electrical Properties of ZnO/Si Heterojunctions Based on ZnO Nanoflakes by Spin Coating Technique

ZnO/Si heterojunctions have been fabricated by spinning ZnO nanoflakes on the p-type single crystal silicon by using the spin coating technique. Photoluminescence spectra of as-grown and annealed ZnO/Si heterojunctions have been recorded under the excitation of 336 nm. Multipeaks between ∼360 nm and ∼430 nm from annealed ZnO/Si heterojunctions have been analyzed, the origins of which have been ascribed to the effects of one or multiple LO phonons. The rectifying effects can be observed from the prototypical devices based on ZnO/Si heterojunctions. Although the parameters obtained by analyzing the current density-voltage characteristics are away from those from the ideal device, it is believed that ZnO/Si heterojunctions in the present work will be a potential candidate in the optoelectronic field through modulating and optimizing the fabrication conditions.