Band alignment and polarization engineering in κ-Ga2O3/GaN ferroelectric heterojunction

Photoconductive and photovoltaic metal-semiconductor-metal κ-Ga2O3 solar-blind detectors with high rejection ratios

“…There are no observable peaks related to other κ-Ga 2 O 3 orientations and different Ga 2 O 3 polymorphs, which suggests that the hetero-epitaxy of pure-phase κ-Ga 2 O 3 is achieved, and the out-of-plane epitaxial relationship is (001) κ-Ga 2 O 3 || (0001) Al 2 O 3 [12]. In terms of the first-principles calculations, the lattice expansion and the formation energy of Ga 2 O 3 polymorphs are in the tendency of β < κ < α [3,13]. Therefore, κ-Ga 2 O 3 phase is stable at a proper temperature of 525 • C, mediated by the misfit-induced strain [14].…”

“…The semi-stable κ-Ga 2 O 3 has unique merits that are absent in the most stable β-Ga 2 O 3 , including the favorable * Author to whom any correspondence should be addressed. heteroepitaxial characteristics, great compatibility with common substrates and the possibility of polarization engineering endowed by its ferroelectric polar nature [1][2][3]. Extensive research efforts have been made in κ-Ga 2 O 3 for offering the possibility to take semiconductor electronics and photonics into regimes that currently remain out of reach.…”

“…Extensive research efforts have been made in κ-Ga 2 O 3 for offering the possibility to take semiconductor electronics and photonics into regimes that currently remain out of reach. To date, the epitaxy of κ-Ga 2 O 3 and bandgap engineering of κ-(In)Al 2−2x Ga 2x O 3 ternary alloys have been achieved with a large tunable bandgap on numerous substrates with hexagonal or triangular in-plane symmetries, such as sapphire (0001), MgO (111), SrTiO 3 (111), GaN, AlN, 6H-SiC and ZnO [3,4]. Device-oriented implementations based on κ-Ga 2 O 3 , such as solar-blind photodetectors, have also been demonstrated with high performances [5].…”

Density Functional Theory Study of Polarization-Induced Electron Confinement by Dilute Boron Alloying in ε-Ga2O3 Nanometer-Thick Film for High Electron Mobility Transistor

“…Ga 2 O 3 possesses five polymorphs, specifically α, β, γ, δ, and ε. Among these, the ε-phase is noted for its remarkable polarization property, which is an order of magnitude greater than GaN, a semiconductor material typically employed in high electron mobility transistors (HEMTs). , The findings on polarization of ε-phase Ga 2 O 3 have piqued the interest of numerous researchers that are exploring the possibilities of ε-Ga 2 O 3 based devices. − Chen et al have reported on the polarization switching properties of κ-Ga 2 O 3 (where κ and ε denote the same phase of Ga 2 O 3 ) in κ-Ga 2 O 3 /GaN heterostructure, revealing a remanent polarization of approximately 2.7 μC/cm 2 . Wang et al have indicated that the interface of ε-Ga 2 O 3 / m -GaN ( m -AlN) could achieve a high two-dimensional electron gas (2DEG) density of 10 14 cm –2 .…”

“…14−16 Chen et al have reported on the polarization switching properties of κ-Ga 2 O 3 (where κ and ε denote the same phase of Ga 2 O 3 ) in κ-Ga 2 O 3 /GaN heterostructure, revealing a remanent polarization of approximately 2.7 μC/cm 2 . 17 Wang et al have indicated that the interface of ε-Ga 2 O 3 /m-GaN (m-AlN) could achieve a high two-dimensional electron gas (2DEG) density of 10 14 cm −2 . 18 Simultaneously, Kuang et al recorded a 2DEG sheet carrier density of 1.2 × 10 14 cm −2 and enhanced mobility of 192 cm 2 / (V s) within an ε-Ga 2 O 3 /In 2 O 3 heterostructure.…”