Reactive sputtered Zn3N2–CNx hybrid films for silicon heterojunction photodetection

Abstract

Nanohybrid semiconductors comprising distinct nanoscale components offer new opportunities for tailored optoelectronic properties. In this work, Zn₃N₂–CN_x hybrid thin films were prepared by reactive RF magnetron sputtering from a segmented Zn/graphite target and used to fabricate p-Si heterojunction photodetectors. The hybrid-film approach was explored as a route to modify the electronic character of a Zn₃N₂-rich sputtered overlayer and its junction response on silicon. X-ray diffraction and microscopy indicated a heterogeneous nanostructured film, Raman spectroscopy showed retention of a CN_x-like disordered carbon-nitride network, and elemental mapping confirmed spatial coexistence of Zn, N, and C with a measurable O contribution in the as-deposited layer. Optical analysis revealed characteristic energies associated with the Zn₃N₂-rich and CN_x-containing components. The Zn₃N₂–CN_x/p-Si heterojunction exhibited an ideality factor of ∼2.9, a rectification ratio of ∼13.7 at 5 V, a maximum responsivity of ∼0.40 A W⁻¹ at 550 nm, and a detectivity of ∼2.03 × 10¹¹ Jones, together with stable transient switching and rise/recovery times of ∼0.5/0.7 ms. The results support the formation of an electronically distinct hybrid overlayer whose incorporation is associated with improved heterojunction photodetection on p-Si. Reactively sputtered Zn₃N₂–CN_x therefore represents a promising hybrid thin-film platform for Si-based optoelectronic devices.