Band-to-band transitions, selection rules, effective mass, and excitonic contributions in monoclinic β−Ga2O3

作     者：Alyssa Mock Rafał Korlacki Chad Briley Vanya Darakchieva Bo Monemar Yoshinao Kumagai Ken Goto Masataka Higashiwaki Mathias Schubert 

作者机构：Department of Electrical and Computer Engineering and Center for Nanohybrid Functional Materials University of Nebraska-Lincoln Lincoln Nebraska 68588 USA Department of Physics Chemistry and Biology (IFM) Linköping University SE 58183 Linköping Sweden Global Innovation Research Tokyo University of Agriculture and Technology Koganei Tokyo 183-8538 Japan Department of Applied Chemistry Tokyo University of Agriculture and Technology Koganei Tokyo 184-8588 Japan Tamura Corporation Sayama Saitama 350-1328 Japan National Institute of Information and Communications Technology Koganei Tokyo 184-8795 Japan Leibniz Institute for Polymer Research Dresden D-01005 Germany 

出 版 物：《Physical Review B》 (Phys. Rev. B)

年 卷 期：2017年第96卷第24期

页      面：245205-245205页

核心收录：

基　　金：J. A. Woollam Foundation National Science Foundation, NSF, (EPS-1004094) National Science Foundation, NSF Materials Research Science and Engineering Center, Harvard University, MRSEC, (DMR-1420645) Materials Research Science and Engineering Center, Harvard University, MRSEC Stiftelsen för Strategisk Forskning, SSF, (CMMI 1337856, EAR 1521428, FFL12-0181, RIF14-055) Stiftelsen för Strategisk Forskning, SSF Vetenskapsrådet, VR, (VR2013-5580, VR2016-00889) Vetenskapsrådet, VR 

主　　题：Band gap Dielectric properties Electronic structure of atoms & molecules Excitons Semiconductors Single crystal materials Density functional theory Ellipsometry Hybrid functionals Pseudopotentials 

摘      要：We employ an eigenpolarization model including the description of direction dependent excitonic effects for rendering critical point structures within the dielectric function tensor of monoclinic β−Ga2O3 yielding a comprehensive analysis of generalized ellipsometry data obtained from 0.75–9 eV. The eigenpolarization model permits complete description of the dielectric response. We obtain, for single-electron and excitonic band-to-band transitions, anisotropic critical point model parameters including their polarization vectors within the monoclinic lattice. We compare our experimental analysis with results from density functional theory calculations performed using the Gaussian-attenuation-Perdew-Burke-Ernzerhof hybrid density functional. We present and discuss the order of the fundamental direct band-to-band transitions and their polarization selection rules, the electron and hole effective mass parameters for the three lowest band-to-band transitions, and their excitonic contributions. We find that the effective masses for holes are highly anisotropic and correlate with the selection rules for the fundamental band-to-band transitions. The observed transitions are polarized close to the direction of the lowest hole effective mass for the valence band participating in the transition.