Siah, S. C.Brandt, R. E.Lim, K.Schelhas, L. T.Jaramillo, R.Heinemann, M. D.Chua, DannyWright, J.Perkins, J. D.Segre, C. U.Gordon, RoyToney, M. F.Buonassisi, T.2016-06-292015Siah, S. C., R. E. Brandt, K. Lim, L. T. Schelhas, R. Jaramillo, M. D. Heinemann, D. Chua, et al. 2015. Dopant activation in Sn-Doped Ga2O3 investigated by X-Ray absorption spectroscopy. Applied Physics Letters 107: 252103. doi:10.1063/1.4938123.0003-6951http://nrs.harvard.edu/urn-3:HUL.InstRepos:27413726Doping activity in both beta-phase (β-) and amorphous (a-) Sn-doped gallium oxide (Ga2O3:Sn) is investigated by X-ray absorption spectroscopy(XAS). A single crystal of β-Ga2O3:Sn grown using edge-defined film-fed growth at 1725 °C is compared with amorphous Ga2O3:Sn filmsdeposited at low temperature (<300 °C). Our XAS analyses indicate that activated Sn dopant atoms in conductive single crystal β-Ga2O3:Sn are present as Sn4+, preferentially substituting for Ga at the octahedral site, as predicted by theoretical calculations. In contrast, inactive Sn atoms in resistive a-Ga2O3:Sn are present in either +2 or +4 charge states depending on growth conditions. These observations suggest the importance of growing Ga2O3:Sn at high temperature to obtain a crystalline phase and controlling the oxidation state of Sn during growth to achieve dopant activation.en-USJournal Article2016-03-2420152016-06-2910.1063/1.4938123