Band alignments of β-Ga2O3 with MgO, Al2O3 and MgAl2O4 measured by x-ray photoelectron spectroscopy

Liu, Zeng; Yu, Jie; Li, Peigang; Wang, Xia; Zhi, Yusong; Chu, Xuan; Li, Haoran; Wu, Zhenping; Tang, Weihua

doi:10.1088/1361-6463/ab18e0

Cited by 34 publications

(18 citation statements)

References 61 publications

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“…The magnitude of these offsets is similar to those of established dielectrics such as SiO2, Al2O3, HfO2 or HfSiO4 to various other polymorphs of the (AlxGa1-x)2O3/(InxGa1x)2O3 alloy systems [60][61][62] . Therefore, this material might be a promising alternative to these established gate dielectrics in HEMT or other field-effect transistor applications based on Ga2O3, as also recently suggested for the monoclinic modification 63 . The valence band offsets are comparably small and no correlation could be found between the offset magnitude and the Al or In content.…”

Section: Discussionmentioning

confidence: 80%

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Schultz

Kneiß

Storm

et al. 2020

ACS Appl. Mater. Interfaces

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Conduction and valence band offsets are amongst the most crucial material parameters for semiconductor heterostructure device design, such as for high-electron mobility transistors or quantum-well infrared photodetectors. Due to its expected high spontaneous electrical polarization and the possibility of polarization doping at heterointerfaces similar to the AlGaN/InGaN/GaN system, the metastable orthorhombic κ-phase of Ga2O3 and its indium and aluminum alloy systems are a promising alternative for such device applications. However, respective band offsets to any dielectric are unknown, as well as the evolution of the bands within the alloy systems. We report on valence and conduction band offsets of orthorhombic κ-(AlxGa1-x)2O3 and κ-(InxGa1-x)2O3 thin films to MgO as reference dielectric by X-ray photoelectron spectroscopy. The thin films with compositions xIn ≤ 0.27 and xAl ≤ 0.55 were grown by pulsed laser deposition utilizing tin-doped and radially-segmented targets. The determined band alignments reveal the formation of a type I heterojunction to MgO for all compositions with conduction band offsets of at least 1.4 eV, providing excellent electron confinement. Only low valence band offsets with a maximum of ~300 meV were observed. Nevertheless, this renders MgO as promising gate dielectric for metaloxide-semiconductor transistors in the orthorhombic modification. We further found that the conduction band offsets in the alloy systems are mainly determined by the evolution of the bandgaps, which can be tuned by the composition in a wide range between 4.1 and 6.2 eV, since the energy position of the valence band maximum stays almost constant over the complete composition range investigated. Therefore, tunable conduction band offsets of up to 1.1 eV within the alloy systems allow for subniveau transition energies in (AlxGa1-x)2O3/(InxGa1-x)2O3/(AlxGa1x)2O3 quantum wells from the IR to the visible regime, which are promising for application in quantum-well infrared photodetectors.

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Section: Discussionmentioning

confidence: 80%

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Schultz

Kneiß

Storm

et al. 2020

ACS Appl. Mater. Interfaces

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“…Due to the heterojunction fabrication for the first time, for confirming the thin‐film quality, we deposited them for a long time, which may damage the thin‐film surface and/or interface. With the magnetron sputtering system in our lab, the growing temperature of 750 °C is preferable to achieve better quality gallium oxide films . However, the long‐time sputtering could facilitate better crystal and its interface quality at low temperature .…”

Section: Resultsmentioning

confidence: 99%

“…The valves of core energy levels for the Ga 2 O 3 and the Sr 3 Al 2 O 6 are 134 and 1118.49 eV at the Sr 3 Al 2 O 6 /Ga 2 O 3 (SAO/GAO) heterointerface, respectively. Then, the

Δ E_{normalC}

and

Δ E_{normalV}

can be calculated using the following equations

Δ E_{normalV} = {(E_{core} - E_{VBM})}_{GAO} - {(E_{core} - E_{VBM})}_{SAO} - {(E_{core}^{GAO} - E_{core}^{SAO})}_{GAO}^{SAO}

i.e.,

Δ E_{V} = (1118.59 - 1.8) - (133.46 - 1.69) - (1118.49 - 134) = 0.53 eV

…”

Section: Resultsmentioning

confidence: 99%

“…For having the band offsets of Sr 3 Al 2 O 6 /Ga 2 O 3 heterojunction, three samples, including, 1) (100 nm) Sr 3 Al 2 O 6 on Si substrate, 2) (100 nm) Ga 2 O 3 /(100 nm) Sr 3 Al 2 O 6 on Si substrate, and 3) (≈3 nm) Ga 2 O 3 /(100 nm) Sr 3 Al 2 O 6 on Si substrate, were prepared, respectively. XPS was used to measure the binding energies across the heterointerface based on Kraut's method . XPS survey scans were performed to determine the bonding states of Ga 2 O 3 and Sr 3 Al 2 O 6 .…”

Section: Methodsmentioning

confidence: 99%

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Rectifying Effect of the Sr₃Al₂O₆/Ga₂O₃ Heterojunction

Liu

Wang

Zhi

et al. 2019

Physica Status Solidi (a)

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Oxide semiconductors, including binary and ternary oxides, are promising to be utilized as active layers in electronics. The heterojunctions based on oxides exhibit many attractive physical and structural properties and are preferably used to fabricate devices. Herein, Sr 3 Al 2 O 6 /Ga 2 O 3 heterojunction is fabricated using radiofrequency magnetron sputtering on silicon substrate, which shows an enhanced current-voltage characteristic under the 254 nm ultraviolet light illumination due to the photogenerated carriers in Ga 2 O 3 . In addition, the heterojunction provides evident rectified properties in the dark, and the improved rectified properties can be obtained under the 254 nm UV light illumination due to the electron-hole pairs separation in the depletion region due to the built-in electric field, while the rectified ratio decrease from %700 at AE0.5 to %20 V at AE5 V, which is due to the electron tunneling caused by shrinking depletion layer. Moreover, the band offsets of the heterojunction is determined by the X-ray photoelectron spectroscopy, which suggests a type I alignment with conduction band offset of 0.94 AE 0.02 eV and valence band offset of 0.53 AE 0.02 eV. The interfacial energy band offsets verify the potential implication for their rectifying property.

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“…To design an effective unipolar barrier APD device, both interfacial lattice compatibility and energy band offsets need careful consideration. By taking account of our previous experimental results 28 (Supplementary Fig. S1), MgO was incorporated with Ga 2 O 3 to form a unipolar barrier structure possessing a large conduction band offset ΔE C and nearly zero valance band offset ΔE V .…”

Section: Device Fabrication and Characterization Of Epitaxial Heteros...mentioning

confidence: 99%

Enhanced gain and detectivity of unipolar barrier solar blind avalanche photodetector via lattice and band engineering

Zhang

et al. 2023

Nat Commun

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122

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Ga2O3-based solar blind avalanche photodetectors exhibit low voltage operation, optical filter-free and monolithic integration of photodetector arrays, and therefore they are promising to be an alternative to the bulky and fragile photomultiplier tubes for weak signal detection in deep-ultraviolet region. Here, by deliberate lattice and band engineering, we construct an n-Barrier-n unipolar barrier avalanche photodetector consisting of β-Ga2O3/MgO/Nb:SrTiO3 heterostructure, in which the enlarged conduction band offsets fortify the reverse breakdown and suppress the dark current while the negligible valance band offsets faciliate minority carrier flow across the heterojunction. The developed devices exhibit record-high avalanche gain up to 5.9 × 105 and detectivity of 2.33 × 1016 Jones among the reported wafer-scale grown Ga2O3-based photodetectors, which are even comparable to the commercial photomultiplier tubes. These findings provide insights into precise manipulation of band alignment in avalanche photodetectors, and also offer exciting opportunities for further developing high-performance Ga2O3-based electronics and optoelectronics.

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Band alignments of β-Ga₂O₃ with MgO, Al₂O₃ and MgAl₂O₄ measured by x-ray photoelectron spectroscopy

Cited by 34 publications

References 61 publications

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Rectifying Effect of the Sr₃Al₂O₆/Ga₂O₃ Heterojunction

Enhanced gain and detectivity of unipolar barrier solar blind avalanche photodetector via lattice and band engineering

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Band alignments of β-Ga2O3 with MgO, Al2O3 and MgAl2O4 measured by x-ray photoelectron spectroscopy

Cited by 34 publications

References 61 publications

Band Offsets at κ-([Al,In]xGa1–x)2O3/MgO Interfaces

Band Offsets at κ-([Al,In]xGa1–x)2O3/MgO Interfaces

Rectifying Effect of the Sr3Al2O6/Ga2O3 Heterojunction

Enhanced gain and detectivity of unipolar barrier solar blind avalanche photodetector via lattice and band engineering

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Product

Resources

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Band alignments of β-Ga₂O₃ with MgO, Al₂O₃ and MgAl₂O₄ measured by x-ray photoelectron spectroscopy

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Band Offsets at κ-([Al,In]_xGa_1–x)₂O₃/MgO Interfaces

Rectifying Effect of the Sr₃Al₂O₆/Ga₂O₃ Heterojunction