Resumen de Properties of Semiconductors: Synthesis of Oriented ZnO for Photoelectrochemistry and Photoremediation
Emma Koenig, Ari Jacobs, George Lisensky
Semiconductors are an important class of materials; preparing ZnO nanorods allows semiconducting properties to be easily observed. The week before lab, groups of four students take 15 min to setup two fluorine-doped tin oxide glass (FTO) slides in a zinc nitrate and hexamethylenetetramine solution stored at 90 °C until the next lab. Hexagonal ZnO nanorods oriented along the c-axis are produced, as shown by X-ray diffraction (XRD) and scanning electron microscopy (SEM) images. Semiconductor properties are observed by measuring the band gap by UV–visible absorption spectroscopy and exposing samples to UV light to excite electrons into the conduction band. One pair of students obtains SEM and photoelectrochemical measurements, while the other pair obtains an absorption spectrum, XRD scan, and methylene blue kinetic data. The primary pedagogic goal of the experiment is to reinforce semiconductor concepts where two teams collaborate to summarize their evidence that ZnO is a semiconductor.
