Epitaxial Growth of Alpha Gallium Oxide Thin Films on Sapphire Substrates for Electronic and Optoelectronic Devices: Progress and Perspective

Gallium Oxide Nanostructures: A Review of Synthesis, Properties and Applications

“…The arrangement of atoms in gallium oxide determines the different structures of gallium oxide, which are referred to as polymorphs (Table . 1). For instance, α-Ga2O3(rhombohedral), β-Ga2O3 (monoclinic), γ-Ga2O (defective spinel), δ-Ga2O3 (cubic), ε-Ga2O3 (orthorhombic) [18,[49][50][51]. The lattice parameter variations in the cell structures are responsible for these changes in the structure of the material.…”

“…The α-Ga2O3 structure can be maintained only at around 550 °C and above that a phase transformation to β-Ga2O3 takes place. [18,51,53] Figure 2. Transformation of Gallium oxide polymorphs to β-Ga 2 O 3 [52].…”

“…The α-Ga2O3 structure can be maintained only at around 550 °C and above that a phase transformation to β-Ga2O3 takes place. [18,51,53] This structure is another common structure, apart from beta gallium oxide. It has a similar corundum structure to Al 2 O 3 .…”

A Comprehensive Review on Recent Developments in Ohmic and Schottky Contacts on Ga2O3 for Device Applications

“…To date, dislocation density less than 10 3 cm –2 was achieved in β-Ga 2 O 3 , which is low enough to be suitable for power device applications, while in the α phase, the dislocation density is very high, greater than 10 6 cm –2 , due to large lattice mismatch and large thermal expansion coefficient mismatch that have yet to be reduced. Though fabrication of Schottky barrier diodes (SBDs), field-effect transistors (FETs), and solar-blind photodetectors has been reported with α-Ga 2 O 3 using Ti as ohmic contact and PtO x , AgO x , Ni, and Pt as Schottky contacts, − much more attention has been focused on β-Ga 2 O 3 due to its stability. At present, the only commercial Ga 2 O 3 device is a SBD manufactured by Flosfia, Inc., of Japan using mist chemical vapor deposition (CVD) produced α-Ga 2 O 3 . , In this review, we focus on the literature related to β-Ga 2 O 3 based metal–semiconductor structures.…”

“…Because of the prominence of Ga 2 O 3 , its characteristics and applications have been addressed in several references. ,,,,,− This review mainly focuses on metal contacts with β-phase gallium oxide. Following a brief introduction to the physics of metal–semiconductor contacts (MS), the literature on ohmic and Schottky contacts (SCs) on β-Ga 2 O 3 has been reviewed.…”