Nanocrystalline ZnSnN₂ Prepared by Reactive Sputtering, Its Schottky Diodes and Heterojunction Solar Cells

ZnSnN₂ has potential applications in photocatalysis and photovoltaics. However, the difficulty in preparing nondegenerate ZnSnN₂ hinders its device application. Here, the preparation of low-electron-density nanocrystalline ZnSnN₂ and its device application are demonstrated. Nanocrystalline ZnSnN₂ was prepared with reactive sputtering. Nanocrystalline ZnSnN₂ with an electron density of approximately 10¹⁷ cm^-3 can be obtained after annealing at 300 °C. Nanocrystalline ZnSnN₂ is found to form Schottky contact with Ag. Both the current I vs. voltage V curves and the capacitance C vs. voltage V curves of these samples follow the related theories of crystalline semiconductors due to the limited long-range order provided by the crystallites with sizes of 2-10 nm. The I-V curves together with the nonlinear C-V curves imply that there are interface states at the Ag-nanocrystalline ZnSnN₂ interface. The application of nanocrystalline ZnSnN₂ to heterojunction solar cells is also demonstrated.