Influence of in-situ annealing ambient on p-type conduction in dual ion beam sputtered Sb-doped ZnO thin films

Abstract

Sb-doped ZnO (SZO) films were deposited on c-plane sapphire substrates by dual ion beam sputtering deposition system and subsequently annealed in-situ in vacuum and in various proportions of O2/(O2 + N2)% from 0% (N2) to 100% (O2). Hall measurements established all SZO films were p-type, as was also confirmed by typical diode-like rectifying current-voltage characteristics from p-ZnO/n-ZnO homojunction. SZO films annealed in O2 ambient exhibited higher hole concentration as compared with films annealed in vacuum or N2 ambient. X-ray photoelectron spectroscopic analysis confirmed that Sb5+ states were more preferable in comparison to Sb3+ states for acceptor-like SbZn-2VZn complex formation in SZO films.

ZnO Doping and Defect Engineering—A Review

“…The thermal activation energy for Sb acceptor was found to be 115 ± 5 meV, close to the theoretical prediction [56]. A similar acceptor-like Sb Zn -2V Zn complex formation was observed for Sb-doped ZnO (SZO) thin films fabricated by dual ion beam sputtering technique [106]. The SZO films exhibited hole concentration, mobility, and resistivity values of 1.356 × 10 17 cm −3 , 6.737 cm 2 /V s, and 6.842 Ω-cm, respectively.…”

Origin of p-type conductivity of Sb-doped ZnO nanorods and the local structure around Sb ions

“…As reported by previous study, 24 rather than Zn or itself and the Sb-O bond has been proven to be present in the Sb-doped ZnO. 25 Therefore, the increase in the Sb valence state implies that more O ions are bound to the doped Sb ions than to Zn ions in the ZnO lattice.…”

Sb-related defects in Sb-doped ZnO thin film grown by pulsed laser deposition

“…The XPS study on the chemical state of Sb in the ZnO:Sb (2%) samples upon different annealing temperatures showed that the Sb 5þ /Sb 3þ ratio in the samples anti-correlates with the electron concentration and correlates with the V Zn -Sb acceptor complex concentration. Pandey et al 33 carried out the XPS study on Sb-doped ZnO fabricated by dual ion beam sputtering and a high Sb 5þ /Sb 3þ ratio was correlated with the hole concentration, and thus the Sb Zn -2V Zn shallow acceptor. This result is consistent with the assignment of the V Zn -Sb acceptor complex to Sb Zn -2V Zn , rather than Sb i -3V Zn as Sb i -3V Zn is a deep acceptor.…”

“…Figures 12(a)-12(c), respectively, show the XPS spectra of the Sb 3d 3/2 state of the as-grown ZnO:Sb (2%) sample and those upon annealing at 750 and 900 C. The 3d 3/2 peaks were fitted by the Sb 3þ and Sb 5þ peaks locating at $540.2 eV and 540.8 eV, respectively. 33 The fitted intensity ratios of the peaks Sb 5þ /Sb 3þ are 1.61, 4.82, and 2.33 for the as-grown, 750, and 900 C annealed ZnO:Sb samples, respectively. The maximum Sb 5þ /Sb 3þ intensity ratio at the annealing temperature of 750 C well anti-correlates with the minimum of the electron concentration (see Fig.…”