Annealing and surface conduction on Hydrogen peroxide treated bulk melt-grown, single crystal ZnO

• Published in: Physica. B, Condensed matter Condensed matter, 2012-05, Vol.407 (10), p.1624-1627
• Main Authors: Mtangi, W., Nel, J.M., Auret, F.D., Chawanda, A., Diale, M., Nyamhere, C.
• Format: Article
• Language: English
• Subjects: Annealing; Channels; Condensed matter; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Energy levels; Exact sciences and technology; Hall effect; Hydrogen peroxide; Ii-vi semiconductors; Mathematical analysis; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Photoluminescence; Physics; Shallow donors; Single crystals; Surface conduction; Zinc interstitials; Zinc oxide
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2011.09.101

We report on the studies carried out on hydrogen peroxide treated melt-grown, bulk single crystal ZnO samples. Results show the existence of two shallow donors in the as-received ZnO samples with energy levels (37.8±0.3)meV that has been suggested as Zni related and possibly H-complex related and (54.5±0.9)meV, which has been assigned to an Al-related donor. Annealing studies performed on the hydrogen peroxide treated samples reveal the existence of a conductive channel in the samples in which new energy levels have been observed, Zn vacancies, related to the Group I elements, XZn. The surface donor volume concentration of the conductive channel was calculated from a theory developed by Look (2007) [1]. Results indicate an increase in the surface volume concentration with increasing annealing temperature from 60×1017cm−3 at 200°C to 4.37×1018cm-3 at 800°C.