2018/08/01 by Robin Ahrling, Ahrling, Robin, Johannes Boy +13
Energy · Materials Science · #Advanced Photocatalysis Techniques #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Ga2O3 and related materials #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.1808.00308
openalex publication_date 2018/08/01 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
Thin films of the wide band gap semiconductor β-Ga2O3 have a high potential for applications in transparent electronics and high power devices. However, the role of interfaces remains to be explored. Here, we report on fundamental limits of transport properties in thin films. The conductivities, Hall densities and mobilities in thin homoepitaxially MOVPE grown (100)-orientated β-Ga2O3 films were measured as a function of temperature and film thickness. At room temperature, the electron mobilities ((115±10) (cm2)/(Vs)) in thicker films (> 150 nm) are comparable to the best of bulk. However, the mobility is strongly reduced by more than two orders of magnitude with decreasing film thickness ((5.5±0.5) (cm2)/(Vs) for a 28 nm thin film). We find that the commonly applied classical Fuchs-Sondheimer model does not explain the contribution of electron scattering at the film surfaces sufficiently. Instead, by applying an electron wave model by Bergmann, a contribution to the mobility suppression due to the large de Broglie wavelength in β-Ga2O3 is proposed as a limiting quantum mechanical size effect.