α-Si 3 N 4 dendrites and whiskers fabricated using electron irradiation technology

Silicon nitride (Si 3 N 4 ) has great potential for applications in photoelectric and semiconductor fields. In this study, a novel strategy of fabricating Si 3 N 4 crystals is reported, and the morphology of α-Si 3 N 4 can be controlled. The aBN/SiO 2 /Si wafers were designed and irradiated by a high-energy electron beam for 2 min using home-made equipment. Tree-like α-Si 3 N 4 dendrites and [001]-oriented unbranched α-Si 3 N 4 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-Si 3 N 4 exhibit unique photoluminescence properties. This is attributed to α-Si 3 N 4 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 Si 3 N 4 crystals, as well as developing related high-performance micro- or nano-devices.