Regensburg 2019 – wissenschaftliches Programm
HL 16.12: Vortrag
Dienstag, 2. April 2019, 12:30–12:45, H34
IR-Vis-UV optical properties of α-Ga2O3 films grown by halide vapor phase epitaxy — •Pingfan Ning1, Martin Feneberg1, Jürgen Bläsing1, Hoki Son2, Dae-Woo Jeon2, and Rüdiger Goldhahn1 — 1Institut für Physik, Otto-von-Guericke-Universität Magdeburg — 2Korea Institute of Ceramic Engineering & Technology, 15-5, Chungmugong-dong, Jinju-si, Gyeongsangnam-do
Ultra wide band gap semiconductor α-Ga2O3 has been attracting increasing interest due to their potential advantages in UV optoelectronics, power devices, RF electronics as well as transparent electronics. However, many basic physical properties are still unclear, including optical properties, which must be investigated in detail to fully exploit their functions. We investigated the linear optical response of metastable α-Ga2O3 epitaxial layers by spectroscopic ellipsometry. The α-Ga2O3 films are grown on (0001) α-Al2O3 substrates by halide vapor phase epitaxy method while the precursors GaCl and O2 are controlled in different ways. The ordinary dielectric function has been determined by point-by-point fitting of the ellipsometry data from the infrared (300 cm−1) to the ultraviolet (6.5 eV). Effects of GaCl and O2 gas controlling on the infrared-active phonon modes, dielectric limits, and interband transitions are discussed. The infrared dielectric function is accurately described with a sum of Lorentzian oscillators and the dielectric limit. Characteristic energies, broadening factors, and amplitudes of three out of the four expected Eu infrared-active modes are determined.