Structural and electronic-structure investigations of defects in Cu-ion-implanted SnO2 thin films

• Published in: Vacuum 2020-09, Vol.179, p.109481, Article 109481
• Main Authors: Chaudhary, Surekha, Saraswat, Himani, Devi, Devarani, Kulriya, Pawan, Singh, Fouran, Won, Sung-Ok, Shin, Hyun-Joon, Parkash, Jai, Sharma, Aditya
• Format: Article
• Language: English
• Subjects: NEXAFS; SnO2; Thin films; XRD
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2020.109481

SnO2 thin films have been deposited on Si substrates using RF-magnetron sputtering and implanted by 200 keV Cu− ions with ion fluence of 2.79 × 1016 ion/cm2 and 4 × 1016 ion/cm2. Post annealing is done on the pristine and Cu− ion-implanted SnO2 thin films. Samples were characterized using the grazing-incidence X-ray diffraction (GIXRD), field-emission scanning electron microscopy (FESEM) and near-edge X-ray absorption fine structure (NEXAFS). After the annealing, amorphous to crystalline phase transition and growth of particles are seen. It is also evidenced that Cu ions do not make metallic/oxide phases up to the implantation dose of 2.79 × 1016 ion/cm2. Cu L-edge NEXAFS has confirmed the Cu2+ ions in the samples. The O K-edge NEXAFS spectra of annealed films have shown diminished peak intensity of O 2p to Sn 5s hybridized orbitals which signify the O vacancy formation. A pre-edge peak in the O K-edge NEXAFS of Cu implanted films has evolved and confirms the additional hybridization of unoccupied Cu d orbitals with O 2p orbitals. The improved intensity of Sn M5,4-edge features is due to the enhanced crystallinity in annealed samples. Ion-solid interaction induced structural and electronic structure amendments are briefly discussed in the light of energy-loss mechanism. •SnO2 films were deposited on Si substrates using RF-sputtering technique.•Ion implantation was done using Cu ions with ion fluence 2.79 × 1016 ion/cm2 and 4 × 1016 ion/cm2.•Amorphous to crystalline phase change, grain growth and release of strain is studied by GIXRD.•O vacancy formation is confirmed by O K-edge NEXAFS.•Additional hybridization of unoccupied Cu d orbitals with O 2p orbitals is also studied.