In-related complex defects and emission of in-doped ZnO nanocrystal films

• Published in: Physica. E, Low-dimensional systems & nanostructures Vol. 113; pp. 137 - 142
• Main Authors: Torchynska, T.V., El Filali, B., Polupan, G.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2019
• Subjects: In doping; In interstitial complex defects; NBE emission; Substitutional InZn defects; ZnO photoluminescence; In doping; Substitutional InZn defects; NBE emission; In interstitial complex defects; ZnO photoluminescence
• ISSN: 1386-9477; 1873-1759
• DOI: 10.1016/j.physe.2019.05.014

ZnO nanocrystal (NC) films grown by ultrasonic spray pyrolysis, doped with the In atoms in different concentrations and annealed at 400 °C for 4 h in nitrogen flow have been studied. The scanning electron microscopy (SEM), X ray diffraction (XRD), photoluminescence (PL) and X-ray photo electronic spectroscopy (XPS) have been used. It was shown that the PL intensity of near band edge (NBE) emission enlarges significantly and the PL intensity of green PL band suppresses at small In contents ≤ 2.0 at%. The later confirms the occupation of zinc vacancies by In ions with the formation of the substitutional InZn donor defects and ZnO crystal quality improving. At higher In contents the new NBE emission band B (3.034eV) appears in PL spectra and its peak shifts to lower energy with In content increasing. The joint analysis of PL and XRD results permits to suppose that the defects responsible for the PL band B are some complexes, which were formed by the coagulation of the substitutional and interstitial In atoms. Simultaneously, the PL intensity and ZnO film crystallinity falling down and the ZnO crystal lattice parameters increase. To study a nature of the In related complex defects, XPS spectra have been investigated for the films with the different In contents. XPS spectrum varying versus In contents has confirmed the complex In defect nature. The dependence of Ini complex defect formation versus In contents in ZnO NC films is analyzed and discussed. The optimal In concentration range to fabricate the ZnO films with high optical parameters has been estimated. •ZnO NC films grown by ultrasonic spray pyrolysis with different In doping have been studied.•The optimal In doping for high crystal quality and film planar morphology has been estimated.•New NBE emission band appears and its peak shifts to lower energy at higher In contents.•New NBE band B is attributed to emission of donor bound excitons at In related complex defects.•XPS study has confirmed the In atom coagulation at higher In contents in the ZnO films.