Enhanced red shift in optical absorption edge and photoelectrochemical performance of N-incorporated gallium oxide nanostructures

This research paper reports enhanced red shift in the optical bandgap of beta-Ga2O3 films. Intrinsic and N-incorporated beta-Ga2O3 nanostructures were deposited on Si substrates by the hydrogen reducing-ambient chemical vapor deposition method. The effects of N addition on the structural, morphological, optical and photo electrochemical properties were studied appropriately. X-ray diffraction analysis showed decreasing crystallite size from 165.2 to 38.2 nm with increasing NH3 flow rate. Microstructural observations by field-emission scanning electron microscope exhibited morphology transformation from nanobelts to full nanoclumps. Energy dispersive X-ray analysis revealed N concentration from 0 up to 17.1 at.% with rising ammonia flow rate. Optical reflectance measurements by UV-vis-NIR spectrophotometer showed enhanced narrowing of optical bandgap from 4.87 to 3.54 eV attributed to rising N content. Photoelectrochemical performance of the doped beta-Ga2O3 films, measured in 0.1 M HCl electrolyte showed significant photoresponse with photocurrent density up to 0.347 mA/cm(2) and (similar to) 0.1% photon-to-current conversion efficiency.