α-Si3N4 dendrites and whiskers fabricated using electron irradiation technology

Abstract

Silicon nitride (Si₃N₄) has great potential for applications in photoelectric and semiconductor fields. In this study, a novel strategy of fabricating Si₃N₄ crystals is reported, and the morphology of α-Si₃N₄ can be controlled. The aBN/SiO₂/Si wafers were designed and irradiated by a high-energy electron beam for 2 min using home-made equipment. Tree-like α-Si₃N₄ dendrites and [001]-oriented unbranched α-Si₃N₄ whiskers can be synthesized by controlling the electron beam energy. Related formation mechanisms were analyzed based on componential and structural characterization using a scanning electron microscope and high-resolution transmission electron microscope. In addition, photoluminescence measurements indicate that the synthesized α-Si₃N₄ exhibit unique photoluminescence properties. This is attributed to α-Si₃N₄ forming abundant Si–Si bonds, Si dangling bonds, N dangling bonds and oxygen bonds in the synthesis process. These findings provide new insights into fabricating high-quality Si₃N₄ crystals, as well as developing related high-performance micro- or nano-devices.