(AlGa)_2O_3 solar-blind photodetectors on sapphire with wider bandgap and improved responsivity

Feng, Qian; Li, Xiang; Han, Genquan; Huang, Lu; Li, Fuguo; Tang, Weihua; Zhang, Jincheng; Hao, Yue

doi:10.1364/ome.7.001240

Cited by 86 publications

(54 citation statements)

References 21 publications

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“…We obtained a bowing parameter of 1.6 eV for α and 1.0 eV for the β-(Al x Ga 1−x ) 2 O 3 alloys. Overall, our results are in good agreement with the available experimental data [16][17][18][19][20], also shown in Figure 4. Due to the stability of the ordered AlGaO 3 (x = 0.5), we can define two independent bowing parameters, one for 0 ≤ x ≤ 0.5 and another for 0.5 ≤ x ≤ 1.…”

supporting

confidence: 91%

“…Bulk and thin films of β-(Al x Ga 1−x ) 2 O 3 have been obtained using solution combustion synthesis [16], pulsed laser deposition (PLD) [17], and oxygen plasmaassisted molecular beam epitaxy (MBE) [10][11][12], while α- up to 81% [18,19]. Band gaps of (Al x Ga 1−x ) 2 O 3 for selected Al content have been reported [16][17][18][19][20], but band offsets between Ga 2 O 3 and (Al x Ga 1−x ) 2 O 3 , which are much more challenging to obtain experimentally, are still unknown.…”

mentioning

confidence: 99%

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Band Gap and Band Offset of Ga2O3 and (AlxGa<

Wang

et al. 2018

Phys. Rev. Applied

127

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Ga2O3 and (AlxGa1−x)2O3 alloys are promising materials for solar-blind UV photodetectors and high-power transistors. Basic key parameters in the device design, such as band gap variation with alloy composition and band offset between Ga2O3 and (AlxGa1−x)2O3, are yet to be established. Using density functional theory with the HSE hybrid functional, we compute formation enthalpies, band gaps, and band edge positions of (AlxGa1−x)2O3 alloys in the monoclinic (β) and corundum (α) phases. We find the formation enthlapies of (AlxGa1−x)2O3 alloys are significantly lower than of (InxGa1−x)2O3, and that (AlxGa1−x)2O3 with x=0.5 can be considered as an ordered compound AlGaO3 in the monoclinic phase, with Al occupying the octahedral sites and Ga occupying the tetrahedral sites. The band gaps of the alloys range from 4.69 to 7.03 eV for β-(AlxGa1−x)2O3 and from 5.26 to 8.56 eV for α-(AlxGa1−x)2O3. Most of the band offset of the (AlxGa1−x)2O3 alloy arises from the discontinuity in the conduction band. Our results are used to explain the available experimental data, and consequences for designing modulation-doped field effect transistors (MODFETs) based on (AlxGa1−x)2O3/Ga2O3 are discussed.

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confidence: 91%

mentioning

confidence: 99%

Band Gap and Band Offset of Ga2O3 and (AlxGa<

Wang

et al. 2018

Phys. Rev. Applied

127

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“…Besides, it possesses the controllable carrier concentration [23][24][25][26]. Although there have been various reported methods for growing (AlGa) 2 O 3 alloy, effective usage of a high aluminum content (Al > 60 at.%) is indeed desired for broadening the bandgap of (AlGa) 2 O 3 sesquioxides to VUV region (> 6 eV) [27][28][29][30]. However, limited by the compatibility with substrate materials, the increase of aluminum content usually causes (AlGa) 2 O 3 sesquioxides to transform into amorphous phase, which hampers the preparation of high-performance VUV detectors.…”

Section: Introductionmentioning

confidence: 99%

“…However, (AlGa) 2 O 3 detectors with high aluminum contents are still constrained within planar photoconductive types, because the sapphire substrates are not conductive for transmitting carriers [27][28][29] and triethyl-gallium (TEGa) were used as precursors for the film growth.…”

Section: Introductionmentioning

confidence: 99%

Ultrawide-bandgap (6.14 eV) (AlGa)2O3/Ga2O3 heterostructure designed by lattice matching strategy for highly sensitive vacuum ultraviolet photodetection

Zhang

Jia

et al. 2021

Sci. China Mater.

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One judiciously designed strategy of utilizing an ultrathin but conductive Ga 2 O 3 :Si nanolayer to prepare (AlGa) 2 O 3 crystalline film is demonstrated. Benefiting from the existence of Ga 2 O 3 :Si nanolayer, a high-quality (Al 0.68 Ga 0.32 ) 2 O 3 sesquioxide film with 68 at.% aluminum was epitaxially grown on sapphire substrates, which was characterized by high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. Its bandgap was broadened to 6.14 eV, and a vacuum ultraviolet (VUV) (AlGa) 2 O 3 /Ga 2 O 3 :Si photodetector was subsequently fabricated. The detector exhibits a pretty high on-off ratio of about 10 3 , an open-circuit voltage of 1.0 V and a responsivity of 8.1 mA W −1 at 0 V bias voltage. The performances imply that the proposed strategy is valuable for improving the quality and also adjusting the bandgap of (AlGa) 2 O 3 sesquioxides, which is expected to facilitate their application in VUV photodetection.

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“…As the bandgap increases with Al content [10,12,13,22,23,24], it was expected that the device fabricated with (Al x Ga 1−x ) 2 O 3 with high Al content would offer even higher efficiency. However, significantly degraded device efficiency was reported at high Al content beyond ∼25% [20,25]. This reduced efficiency is due to the crystallinity degradation of (Al x Ga 1−x ) 2 O 3 , arising from the solubility limit of corundum Al 2 O 3 in monoclinic Ga 2 O 3 beyond a certain Al content [10,12,26,27,28,29,30].…”

Section: Introductionmentioning

confidence: 99%

Probing structural and chemical evolution in (AlxGa1−x)2O3 using atom probe tomography: A review

Mazumder

Sarker

2021

Journal of Materials Research

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Abstract(AlxGa1−x)2O3 is a novel ultra‐wide bandgap semiconductor with the potential to dominate future power electronics industries. High‐performance devices demand high Al content in (AlxGa1−x)2O3 but are limited by crystallinity degradation resulting from phase separation. Additionally, the solubility limit of Al is still under debate, and conclusive research is in progress. (AlxGa1−x)2O3 is also limited in high‐frequency applications owing to low carrier mobility and requires n‐type doping. For commercializing this material, the major obstacle is understanding dopant's behavior in the host (AlxGa1−x)2O3. To investigate these issues, an advanced characterization technique, atom probe tomography (APT), was employed to analyze the structural‐chemical evolution of (AlxGa1−x)2O3. In this review, we summarized our recent works on the structure‐chemistry investigation of (AlxGa1−x)2O3 with alloy composition and doping interaction. We introduced machine learning algorithms on APT data to reveal unrivaled knowledge, previously not achievable with conventional methodologies. The outstanding capabilities of APT to study (AlxGa1−x)2O3 with Al composition and doping will be considered significant for the wide bandgap semiconductors community.

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(AlGa)_2O_3 solar-blind photodetectors on sapphire with wider bandgap and improved responsivity

Cited by 86 publications

References 21 publications

Band Gap and Band Offset of Ga2O3 and (AlxGa<

Band Gap and Band Offset of Ga2O3 and (AlxGa<

Ultrawide-bandgap (6.14 eV) (AlGa)2O3/Ga2O3 heterostructure designed by lattice matching strategy for highly sensitive vacuum ultraviolet photodetection

Probing structural and chemical evolution in (AlxGa1−x)2O3 using atom probe tomography: A review

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