Description: The project will experimentally test the performance of predicted disperse valence band material ZrOS, which is expected to show high hole mobility and high transparency, in addition to being p-type dopable . Combinatorial thin films of Zr with concentration gradients in selected dopant atoms (e.g. Ba, Zn, Y) will be deposited by sputtering at EPFL’s PV-Lab and sent to the student at Twente for sulfurization. The first objective will be to obtain the correct phase, which will be assessed using X-ray diffraction measurements taken before and after each sulfurization treatment. Variations in sulfurization time, temperature, tube oven geometry, and other relevant variables will be undertaken by the student to successfully achieve the oxy-sulfide material, with the possibility of developing a two-step synthesis route: i.e. sulfurization to zirconium sulfide, followed by controlled oxidation to obtain ZrOS. Additional characterization will be performed as necessary to confirm phase changes and the effect on material properties, such as UV-Vis-NIR spectroscopy and electrical characterization by PPMS. Samples will then be sent to collaborators in Switzerland for chemical characterization by X-ray fluorescence (XRF) and X-ray photoelectron spectroscopy (XPS). The student will gain experience working with thin films and tube furnaces in a chemical lab, and will learn thin film x-ray diffraction (XRD) and data analysis techniques, all while participating in an international collaboration.
 T. Arai et al. ‘Chemical Design and Example of Transparent Bipolar Semiconductors’. JACS 139 (47) 2017. DOI: 10.1021/jacs.7b09806
Monica Morales-Masis, C3237, firstname.lastname@example.org, +31534891791