Comprehensive Raman study of orthorhombic κ/ε-Ga₂O₃ and the impact of rotational domains

Abstract

Gallium oxide (Ga2O3) is an ultra-wide bandgap material, which has recently attracted widespread attention for holding promising applications in power electronics and as solar blind UV photodetectors, outclassing GaN or...

Silane‐Mediated Expansion of Domains in Si‐Doped κ‐Ga2O3 Epitaxy and its Impact on the In‐Plane Electronic Conduction

“…Only modes typical of the orthorhombic polymorph of Ga 2 O 3 were identified (aside from the ones of the c-plane sapphire), [38] consistent with the XRD and TEM investigations. Despite the different analysis configurations, both surface and edge spectra equivalently highlight similar differences among the analyzed samples, especially when undoped and doped layers are compared (Figure 6a; Figure S9a, Supporting Information).…”

“…[ 29 ] The c unit cell parameter (evaluated from 2θ‐θ XRD scans) does not seem to be majorly affected by the $${\Phi _{{\rm{Si}}{{\rm{H}}_4}}}$$ in our samples: the recorded c variations (between ≈ 9.260 and 9.275 Å) are well in line with previously reported data for the orthorhombic Ga 2 O 3 polymorph. [ 38 ] This is likely related to the limited amount of provided Si, as well as the non‐trivial role of the Si‐Ga aliovalent substitution and related defects (see following subsections).…”

“…Typical collection time for the confocal configuration was 60 s for each acquisition, with 10 repetitions. Additional measurements in cross‐sectional configuration [ 38 ] with a λ = 532 nm were performed with another LabRAM HR 800 spectrometer (Horiba Jobin‐Yvon).…”

Demonstration of thick phase-pure β-Ga2O3 on a c-plane sapphire substrate using MOCVD

“…The polymorphs of Ga2O3, namely the corundum (α) and orthorhombic (κ) phases have bandgaps in the 4.4 -5.1 eV range [6], [7]. In κ-Ga2O3, the orthorhombic domains are rotated 120° against each other forming a pseudo-hexagonal structure and often called ε-Ga2O3 [8], thus, ε-Ga2O3 and κ-Ga2O3 terms are used interchangeably to refer to orthorhombic Ga2O3 in literature. The fabrication and operation of Schottky diodes and MESFETs were also demonstrated with α-Ga2O3 and ε-Ga2O3 [9]- [11].…”

Phase Stabilized MOCVD Growth of β‐Ga2O3 Using SiOx on c‐Plane Sapphire and AlN/Sapphire Template

“…[3,12] In κ-Ga 2 O 3 , the orthorhombic domains are rotated 120°against each other, forming a pseudo-hexagonal structure and often called ε-Ga 2 O 3 ; thus, ε-Ga 2 O 3 and κ-Ga 2 O 3 terms are used interchangeably to refer to orthorhombic Ga 2 O 3 in literature. [13] However, the metastable αand ε-Ga 2 O 3 phases convert to more stable β-Ga 2 O 3 at high temperatures. [4] High-quality homoepitaxial β-Ga 2 O 3 layers and high-performance devices on (010), (001), (100), (201) β-Ga 2 O 3 substrates were demonstrated.…”