Three-dimensional heterostructured ZnSe nanoparticles/Si wire arrays with enhanced photodetection and photocatalytic performances

Abstract

P-type micron size silicon wire (SiW) arrays coated with ZnSe nanoparticles (NPs) exhibiting enhanced photodetection and photocatalytic performances were synthesized. The SiWs were grown by combining catalytic etching with nanosphere lithography methods. ZnSe NPs were coated on SiWs with a chemical bath deposition (CBD) method. The high photodetection performance of three-dimensional (3D) heterostructured ZnSe NP/SiW arrays with immediate decay (>99.85%), on/off ratio (>7 × 10²) and photoresponse speed (<0.4 s) was recorded under a small applied voltage (80 μV). The immediate decay and on/off ratio increase with decreasing applied voltage and the photocurrent variations of ZnSe NPs/SiWs were larger than 0.3 μA at 1 V. The enhanced UV photocurrent response is attributed to a large surface-to-volume ratio and the presence of the fast conductive pathway of ZnSe NP/SiW shell/core heterostructures. ZnSe NPs/SiWs also showed superb photocatalytic properties with methylene blue (MB) and acid fuchsin (AF) as reagents. The photodegradation data exhibited high activities of 88% and 83% after 120 and 110 min, respectively. The CBD of ZnSe NPs on SiWs provides a facile route for the fabrication of well aligned 3D heterostructured ZnSe NP/SiW arrays with a high on/off ratio photocurrent and photocatalytic activity.