Electron mobility in CdO films
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Electron mobility in degenerate CdO thin films has been studied as a function of carrier concentration. The "optical" mobility has been determined from infrared reflectance measurements of the conduction band plasmon lifetime. The acquired values vary from ~209 to ~1116 cm(2) V-1 s(-1) for carrier concentrations between 2.5 x 10(20) and 2.6 x 1019 cm(-3). Ionized impurity scattering is shown to be the dominant effect reducing the intra-grain mobility of the electrons at room temperature. The transport mobilities from Hall effect measurements range between similar to 20 and similar to 124 cm(2) V-1 s(-1) which are much lower than the optical mobilities. Simulation of grain boundary scattering-limited mobility is commonly based on models that assume a depletion layer at the boundaries which causes an inter-grain potential barrier. These models are found not to be applicable to CdO as it has been previously shown to have surface electron accumulation. Therefore, simulation of the transport mobility has been performed using the Fuchs-Sondheimer and Mayadas-Shatzkes models to take into account the grain boundary and surface scattering mechanisms, in addition to intra-grain scattering. The results indicate that electron scattering at grain boundaries with similar to 95% reflection is the dominant mechanism in reducing the mobility across the layer. The effect of surface scattering plays only a minor role in electron transport.
Farahani , S K V , Veal , T D , King , P D C , Zuniga-Perez , J , Munoz-Sanjose , V & McConville , C F 2011 , ' Electron mobility in CdO films ' Journal of Applied Physics , vol 109 , no. 7 , pp. 073712 . DOI: 10.1063/1.3562141
Journal of Applied Physics
Copyright 2011, American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics, Vol 109, Issue 7, and may be found at: http://scitation.aip.org/content/aip/journal/jap/109/7/10.1063/1.3562141
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