Method to convert a horizontal furnace to grow ZnO nanowires for gas sensing by the VLS method

Abstract

Zinc oxide (ZnO), II-VI compound semiconductor with a wide band gap (3.4ev), has a stable wurtzite structure with lattice spacing a=0.325 nm and c=0.521nm. Its properties and potential for applications in photovoltaics, LED's, spin electronics, ultraviolet light emitters, chemical sensors and transparent electronics has attracted intensive research. The objective of this thesis is to fabricate ZnO nanowires on gold coated silicon substrates using the chemical vapor transport (CVT) method. Under a constant flow of Argon gas (200mL/min), the substrates along with a mixture of ZnO and graphite powder are placed in a modified horizontal furnace which uses a 2.54 cm internally mounted quartz tube and are exposed to high temperature (527°C-1000°C) for different growth times. This reaction causes the formation of ZnO nanowires on the substrates. scanning electron microscopy is used to measure the size of the nanowires.