Reversible band gap tuning of metal oxide films using hydrogen and oxygen plasmas

Bio‐Inspired Band Gap Engineering of Zinc Oxide by Intracrystalline Incorporation of Amino Acids

“…[ 23 ] Reaction of ZnO crystals with an oxidizing or a reducing environment proved, moreover, that this change was reversible. [ 24 ] It is feasible that the amino acids become incorporated within the ZnO lattice at oxygendefi cient locations, thereby effectively lowering the relative amount of oxygen vacancies, which in turn increases the band gap.…”

Enhancement in SERS intensities of azo dyes adsorbed on ZnO by plasma treatment

“…For detailed procedures of band gap measurement, please refer to the Supporting Information or Reference. In this work, we have found that the ZnO band gap value has a maximum at 550 °C (Fig. S3), which is also the calcination temperature for the optimal SERS intensity.…”

“…The band gap values of ZnO nanoparticles can be determined by using ultraviolet (UV) diffuse reflectance technique . For detailed procedures of band gap measurement, please refer to the Supporting Information or Reference.…”

“…The magnitude of the intensity contributions to SERS spectra is also affected by the excitation wavelengths and nanoparticle sizes used . According to the study of band gap tuning of ZnO, it has been shown that H 2 plasma and O 2 plasma can induce the increase and the decrease, respectively, of the ZnO band gap values. Therefore, plasma‐induced enhancement of SERS intensity can be attributed to the different degrees of coupling between the VB and CB energy levels in ZnO and the HOMO and LUMO energy levels in azo dye molecule.…”

“…Plasma treatment has been utilized to alter the defect contents in ZnO in order to modify band gaps and therefore the optoelectronic properties . It is known that O 2 plasma treatment generates Zn vacancies but reduces oxygen vacancies in ZnO single crystals .…”