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DS: Fachverband Dünne Schichten
DS 20: Focus Session: Emerging oxide semiconductors I (jointly with HL, DF, O)
DS 20.7: Topical Talk
Mittwoch, 2. April 2014, 11:30–12:00, POT 081
Beta-Ga2O3: Single crystal growth and semiconductor applications — •Encarnacion G. Villora1, Daisuke Inomata3, Stelian Arjoca1,2, Kazuo Aoki3, and Kiyoshi Shimamura1,2 — 1National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan — 2Graduate School of Advanced Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 176-0022, Japan — 3Koha Co., Ltd., Nerima, Tokyo 176-0022, Japan
β-Ga2O3 is a unique transparent conductive oxide, which is attracting an increasing attention in the recent years. It possesses two major features. The first is its very wide bandgap Eg=4.8 eV, which leads to a high transparency (>260 nm) and to a Baliga’s figure of merit over three times that of GaN and SiC counterparts. The second feature is the capability to grow crystals from the melt, which makes possible the mass production of large substrates at low cost.
High quality 2 inch single crystals are grown by the EFG technique, and 4 inch are already in progress. N-type carrier concentration is controlled by Si- or Sn-doping. Conductive wafers are used as transparent conductive substrates for high-brightness vertically structured LEDs based on InGaN multi-quantum wells. Schottky barrier diodes and transistors have been demonstrated.
Additionally, a new phosphor concept for high-brightness white LEDs and LDs is presented. In contrast to currently used powder phosphors embedded in resins, single-crystal phosphors exhibit outstanding internal quantum efficiencies and do not degrade either under light irradiation or the increase of temperature.