Solvothermal synthesis of high-aspect ratio alloy semiconductor nanowires: Cd1-xZnxS, a case study

High-aspect ratio Cd1-xZnxS (x ) 0-1) alloy semiconductor nanowires are reported here for the first time using an ethylenediamine (en)-assisted solvothermal approach. The composition of the en-water (en-w) mixed solvent plays a crucial role in determining the morphology and crystalline phase of the alloy nanowires in the middle range of x (i.e., when x approaches 0.5). A phase transformation from hexagonal to cubic was observed for the middle range of x in an en-dominated solvent (en/w, 5:1). Nanowires with hexagonal phases were formed for the entire range of x with increasing water content of the solvent system (en/w, 2:1). The aspect ratio of the nanowires was found to be dependent on the x value as well as solvent composition. Alloy nanowires exhibit photoresponse properties when illuminated under white light. The synthesis technique is modified to synthesize core-shell Cd1-xZnxS/ZnS nanowires. Enhancement in photoluminescence efficiency is observed with a ZnS shell over the alloy nanowires.