| Silicon nanowires were made via oxide-assisted growth (OAG) and electrochemical etching. Growth mechanisms for the various products of the OAG synthesis were proposed based on scanning electron microscopy (SEM). The etching synthesis produced silicon nanowires along with silver dendrites, both of which were characterized by SEM. The nanowires (both syntheses) were etched with HF to yield hydride-terminated wires, though the electrochemically produced wires showed less success. Some nanowires (OAG) exhibited weak photoluminescence.; Metal nanostructures on semiconductors were synthesized by galvanic displacement. Silver plates were formed on GaAs with silver salts. With AgNO3, both phases of silver were present and large, stacked structures formed. When Ag2SO4 was used, only the cubic phase was evident and the plates lie flat on the substrate. The twinning growth mechanism is discussed. Also, regular and semi-regular polyhedral shapes of gold were formed on InP, also via twinning. Other systems studied include Ag/Ge, Pt/InP, and Ag/InP. |
