Infrared to vacuum-ultraviolet ellipsometry and optical Hall-effect study of free-charge carrier parameters in Mg-doped InN
2013 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 113, no 1, 013502- p.Article in journal (Refereed) Published
Infrared to vacuum-ultraviolet spectroscopic ellipsometry and far-infrared optical Hall-effect measurements are applied to conclude on successful p-type doping of InN films. A representative set of In-polar Mg-doped InN films with Mg concentrations ranging from 1.2 x 10(16) cm(-3) to 3.9 x 10(21) cm(-3) is investigated. The data are compared and discussed in dependence of the Mg concentration. Differences between n-type and p-type conducting samples are identified and explained. p-type conductivity in the Mg concentration range between 1.1 x 10(18) cm(-3) and 2.9 x 10(19) cm(-3) is indicated by the appearance of a dip structure in the infrared spectral region related to a loss in reflectivity of p-polarized light as a consequence of reduced LO phonon plasmon coupling, by vanishing free-charge carrier induced birefringence in the optical Hall-effect measurements, and by a sudden change in phonon-plasmon broadening behavior despite continuous change in the Mg concentration. By modeling the near-infrared-to-vacuum-ultraviolet ellipsometry data, information about layer thickness, electronic interband transitions, as well as surface roughness is extracted in dependence of the Mg concentration. A parameterized model that accounts for the phonon-plasmon coupling is applied for the infrared spectral range to determine the free-charge carrier concentration and mobility parameters in the doped bulk InN layer as well as the GaN template and undoped InN buffer layer. The optical Hall-effect best-match model parameters are consistent with those obtained from infrared ellipsometry analysis.
Place, publisher, year, edition, pages
American Institute of Physics (AIP), 2013. Vol. 113, no 1, 013502- p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-88457DOI: 10.1063/1.4772625ISI: 000313329000019OAI: oai:DiVA.org:liu-88457DiVA: diva2:604077
Funding Agencies|National Science Foundation|MRSEC DMR-0820521MRI DMR-0922937DMR-0907475EPS-1004094|Swedish Research Council (VR)|2010-3848|Swedish Governmental Agency for Innovation Systems (VINNOVA) under the VINNMER International Qualification program|2011-03486|FCT Portugal|PTDC/FIS/100448/2008|2013-02-072013-02-072013-02-20