Growth and fundamentals of bulkβ-Ga₂O₃single crystals

Abstract

The rapid development of bulk β-Ga2O3 crystals has attracted much attention to their use as ultra-wide bandgap materials for next-generation power devices owing to its large bandgap (~ 4.9 eV) and large breakdown electric field of about 8 MV/cm. Low cost and high quality of large β-Ga2O3 single-crystal substrates can be attained by melting growth techniques widely used in the industry. In this paper, we first present an overview of the properties of β-Ga2O3 crystals in bulk form. We then describe the various methods for producing bulk β-Ga2O3 crystals and their applications. Finally, we will present a future perspective of the research in the area in the area of single crystal growth.

In-plane crystalline anisotropy of bulk β-Ga2O3

“…-Ga 2 O 3 is the most stable phase among the five polymorphs [, , , and " () phases] of Ga 2 O 3 under ambient conditions (Playford et al, 2013;Roy et al, 1952). It has a wide band gap (4.4-4.8 eV;Onuma et al, 2015), a high critical breakdown electric field (8 MV cm À1 ; Higashiwaki et al, 2012) and a very good transparency (>80% transmittance) in the ultraviolet and visible regions (Galazka et al, 2014), and is readily manufacturable via sophisticated growth technologies Mohamed et al, 2019). Up to now, various growth technologies have been successfully applied in fabricating large -Ga 2 O 3 bulk single crystals and thin films, including edge-defined film-fed growth (EFG), Czochralski and floating zone crystallization, metal-organic vapour phase epitaxy, and mist chemical vapour deposition (von Wenckstern, 2017;Mohamed et al, 2019), of which EFG is the most popular commercialized technology for bulk -Ga 2 O 3 (Kuramata et al, 2016;Guo et al, 2015).…”

Thermal conductivity of AlXGa1-XN and β-Ga2O3 semiconductors

“…Bulk β−Ga 2 O 3 crystals with controllable size can be grown by several well-developed methods such as Verneuil method, floating zone method, Czochralski method, egdedefined-film-fed growth method, and Bridgman method [85]. In all these methods, a liquid phase of Ga 2 O 3 which will crystallize into β−Ga 2 O 3 on the seed materials, is needed.…”

Characterization and mechanical properties of cellulose acetate/carbon nanotube composite nanofibers

“…Cellulose acetate (CA, 39.7% acetyl content, average Mw = 50,000 by GPC) was purchased from Sigma‐Aldrich. Multiwalled carbon nanotubes (MWNTs, diameter: 40 nm, length: 18 μm) were produced, and the procedure is described somewhere else . Acetone and DMF were purchased from Sigma‐Aldrich and used directly without further purification.…”