Development of UHV pulsed laser deposition set-up for in-situ photoelectron spectroscopic study at ARPES beamline, Indus-1 synchrotron radiation source, India

摘要

We have developed an Ultra-High Vacuum (UHV) compatible Pulsed Laser Deposition (PLD) set-up at Angle Resolved Photo Electron Spectroscopy (ARPES) beamline (BL-3) at Indus-1 synchrotron radiation source, Raja Ramanna Centre for Advanced Technology, Indore, India. The set-up is successfully tested and integrated at beamline for in-situ photoelectron spectroscopic (PES) studies of thin films. In present PLD set-up, quick in-situ transfer of deposited thin films to analysis chamber enables the surface sensitive PES measurements on atomically cleaned surfaces without the requirement of any sputtering. This set-up has the capability of thin film depositions using six number of one-inch targets with precise control of various deposition parameters at a base pressure of ~1×10~(-9) mbar. To explore the capability of the system, a set of thin films of HfO_2, 5 % Ga_2O_3 doped ZnO (GZO) and GZO/HfO_2 are deposited and the band offset of GZO/HfO_2 heterostructure is investigated by in-situ PES measurements using synchrotron radiation. The film surface is found to be contamination free, which demonstrates the capability of the set-up for in-situ PES studies. The Hf 4f and Zn 3d core level peaks along with valence band maxima positions are used to determine the valence band offset. The valence band offset is found to be 0.31 ± 0.08 eV, which is the first result reported on this heterostructure system.