Growth, characterization, and properties of bulk SnO2 single crystals. Issue 1 (4th October 2013)

• Record Type: Journal Article
• Authors: Galazka, Zbigniew; Uecker, Reinhard; Klimm, Detlef; Irmscher, Klaus; Pietsch, Mike; Schewski, Robert; Albrecht, Martin; Kwasniewski, Albert; Ganschow, Steffen; Schulz, Detlev; Guguschev, Christo; Bertram, Rainer; Bickermann, Matthias; Fornari, Roberto
• Is Part Of: Physica status solidi. Volume 211:Issue 1(2014:Jan.)
• Page Start: 66
• Page End: 73
• Publication Date: 2013-10-04
• Subjects: Solid state physics -- Periodicals; Solids -- Industrial applications -- Periodicals; 530.41
• DOI: 10.1002/pssa.201330020
• Languages: English
• ISSNs: 1862-6300

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <sec id="pssa201330020-sec-0001" sec-type="section"> <p>SnO<sub>2</sub> is a semiconductor with a wide optical bandgap (3.5 eV), which makes it an attractive transparent semiconducting oxide (TSO) for electronic and opto‐electronic applications. At elevated temperatures it is, however, much more unstable than other TSOs (such as ZnO, Ga<sub>2</sub>O<sub>3</sub>, or In<sub>2</sub>O<sub>3</sub>). This leads to a rapid decomposition even under very high oxygen pressures. Our experiments showed that stoichiometric SnO<sub>2</sub> does not melt up to 2100 °C, in contradiction to earlier published data. Bulk SnO<sub>2</sub> single crystals, that could provide substrates for epitaxial growth, have not been reported so far. Hereby we report on truly bulk SnO<sub>2</sub> single crystals of 1 inch diameter grown by physical vapor transport (PVT). The most volatile species during SnO<sub>2</sub> decomposition is, in addition to oxygen, SnO, which is stable in the gas phase at high temperature and reacts again with oxygen at lower temperatures to form SnO<sub>2</sub>. We identified a relatively narrow temperature window, temperature gradients and a ratio of SnO/O<sub>2</sub> for providing the best conditions for SnO<sub>2</sub> single crystal growth. X‐ray powder diffraction (XRD) proved the single SnO<sub>2</sub> phase. Moreover, by selecting a suitable SnO/O<sub>2</sub> ratio it was possible to obtain either n‐type conductivity with electron concentrations up to 2 × 10<sup>18</sup> cm<sup>−3</sup> and electron mobilities up to 200 cm<sup>2</sup> V<sup>−1</sup> s<sup>−1</sup>, or insulating behavior. The crystals exhibited an optical absorption edge located at 330–355 nm, depending on the crystal orientation, and a good transparency over visible and near infrared (NIR) spectra.</p> </sec> </abstract>