Band alignment of In2O3/β-Ga2O3 interface determined by X-ray photoelectron spectroscopy

Abstract

The energy band alignment of the atomic-layer-deposited In2O3/β-Ga2O3 (2¯01) interface is evaluated by X-ray photoelectron spectroscopy. The X-ray diffraction pattern reveals that the In2O3 film grown at 160 °C is amorphous, while it becomes polycrystalline at a higher deposition temperature of 200 °C. The bandgaps, determined by reflection electron energy loss spectroscopy, are 4.65, 3.85, and 3.47 eV for β-Ga2O3, polycrystalline In2O3, and amorphous In2O3, respectively. Both amorphous and polycrystalline In2O3/β-Ga2O3 interfaces have Type I alignment. The conduction and valence band offsets at the polycrystalline (amorphous) In2O3/β-Ga2O3 interface are 0.35 and 0.45 eV (0.39 and 0.79 eV), respectively. These observations suggest that polycrystalline In2O3 as an intermediate semiconductor layer is beneficial to the barrier reduction of metal/Ga2O3 contact.

Transport Mechanism of Enhanced Performance in an Amorphous/Monoclinic Mixed-Phase Ga2O3 Solar-Blind Deep Ultraviolet Photodetector

“…[51,52,[54][55][56][57][58][59][60][61][62][63][64], the present mixed-phase Ga 2 O 3 films had a large band offset including ∆E V and ∆E C compared with previous research. The band offset of m-Ga 2 O 3 film in the present study completely meets the interface's requirements for the driving force of separating electron-hole pairs.…”

Single-Crystalline All-Oxide α–γ–β Heterostructures for Deep-Ultraviolet Photodetection

“…However, single-crystalline indium oxide (In2O3), an intrinsically n-type transparent conducting oxide (TCO) layer with an optical bandgap of ~3.7 eV, [45][46][47] has the potential to achieve the aforementioned goals and emerge as the material of choice as a conducting interfacial layer between the Ga2O3 and Al2O3 platforms. Recently, Sun et al 46 demonstrated type-I band alignment with narrow conduction-band offset (CBO) and valence-band offset (VBO) of 0.35 and 0.45 eV, respectively, at the polycrystalline β-Ga2O3/In2O3 interface, elucidating the potential of the above heterostructure for reducing the barrier height and enhancing carrier transport in visible-transparent oxide platforms. Similarly, Zhi et al 47 demonstrated an even lower CBO of 0.07 eV in the type-I heterostructure for a pulsed laser deposition (PLD)-grown polycrystalline Ga2O3/In2O3 heterostructure.…”

“…Although using interfacial metal layers or other two-dimensional materials (e.g., transition metal dichalcogenides, hexagonal boron nitride, and graphene , ) could provide the required electrical and optical properties, those methods rely on chemical vapor deposition (CVD), thermal evaporation, and sputtering and typically result in polycrystalline structures that are not ideal for the subsequent growth of high-quality crystal structures. However, single-crystalline indium oxide (In 2 O 3 ), an intrinsically n -type transparent conducting oxide (TCO) layer with an optical band gap of ∼3.7 eV, − has the potential to achieve the aforementioned goals and emerge as the material of choice as a conducting interfacial layer between the Ga 2 O 3 and Al 2 O 3 platforms. Recently, Sun et al demonstrated type-I band alignment with narrow conduction-band offset (CBO) and valence-band offset (VBO) of 0.35 and 0.45 eV, respectively, at the polycrystalline β-Ga 2 O 3 /In 2 O 3 interface, elucidating the potential of the above heterostructure for reducing the barrier height and enhancing carrier transport in visible-transparent oxide platforms.…”

“…Similarly, Zhi et al demonstrated an even lower CBO of 0.07 eV in the type-I heterostructure for a pulsed laser deposition (PLD)-grown polycrystalline Ga 2 O 3 /In 2 O 3 heterostructure. However, although previous studies have investigated the band alignment − and electronic properties of the aforementioned heterostructures, the related crystallinity properties of the as-grown layer were largely limited to amorphous or polycrystalline, , and so those studies shed no light on the high-quality single-crystalline β-Ga 2 O 3 /In 2 O 3 heterostructures that are critical for realizing various high-performing oxide-based optoelectronics devices or platforms. Moreover, optoelectronics applications based on β-Ga 2 O 3 /In 2 O 3 heterostructures grown on Al 2 O 3 -based platforms are yet to be demonstrated.…”

Valence and Conduction Band Offsets for InN and III-Nitride Ternary Alloys on (−201) Bulk β-Ga2O3

“…Band offsets have been reported for most relevant oxides on Ga 2 O 3 in search of candidate gate dielectrics for ultra-wide bandgap electronics. [16][17][18][19][20][21][22][23][24][25][26] In addition, common semiconductor heterojunctions have been reported as well, including Si, SiC, GaN, AlN, and IZGO. [27][28][29][30][31][32] Measuring band offsets for the InN/β-Ga 2 O 3 heterojunction is thus complementary to the reported results for the other III-Nitride materials AlN and GaN.…”