Fabrication of Doped Black Phosphorus Crystal by the Chemical Vapor Transport Method

Black phosphorus (BP) has received growing attention due to its suitable carrier mobility and switching ratio, tunable direct band gap, and strong in-plane anisotropy. In recent years, the applied research of both bulk and few-layer BP has yielded continuous breakthroughs, while the device applications with stable performance have lagged due to their poor environmental stability. Additionally, fabricating high-quality doped BP by a desirable chemical vapor transport (CVT) method has been challenging. Herein, the CVT approach with a constant temperature was employed to fabricate Sb-doped BP (Sb–BP) and Bi-doped BP (Bi–BP) to enhance the performance of pristine BP. The characterizations, including Raman, transmission electron microscopy, atomic force microscopy, and so forth, were employed to study the phase structure and properties of the as-grown crystals. The results suggest that BP and doped BP belong to an orthorhombic structure and show good crystallinity. Distinct from pristine BP, the light absorption and electrochemical properties of orthorhombic BP were improved by doping. Furthermore, the storage time of Sb–BP exceeds 65 days, while the degradation of pristine BP occurs within 38 days in ambient condition. The degradation rate of Sb–BP was slower than that of pristine BP even in the harsh environment, which indicates that the antioxidation of Sb–BP is outstanding. Hence, doping is a viable method to modify the properties of BP. This work provides useful guidance for preparing other doped BP and BP compounds, broadening the application field of the phosphorus family.