One-step synthesis route of the aligned and non-aligned single crystalline α-Si_3N_4 nanowires

This paper reports the bulk synthesis route of the aligned and non-aligned high-quality α-Si_3N_4 nanowires (NWS) which were grown directly from the Si substrate by vapor phase deposition at 1050℃. The as-grown products were characterized by employing XRD, SEM, HRTEM and photoluminescence. The microscopic results revealed that the products consist of single crystalline aligned and nonaligned α-Si_3N_4 NWs having a same diameter range of 30-100 nm and different lengths of about hundreds of microns. The XRD observation revealed that the products consist of α-phase Si_3N_4 NWs. The room temperature PL spectra indicated that the NWs have good emission property. The non-aligned NWs were formed at lower temperature as compared with aligned NWs. Our method is a simple and one-step procedure to synthesize the bulk-quantity and high-purity aligned and non-aligned α-Si_3N_4 NWs at a relatively low temperature. The possible growth mechanism was also briefly discussed.