Alleviating trade-off between responsivity and response speed of Ga₂O₃ solar-blind photodetector via modulation of carrier redistribution and extraction accessibility

Abstract

Suitable bandgap, high solar-blind light sensitivity, and high stability against harsh environments make Ga₂O₃ a promising candidate in the application of solar-blind photodetectors. However, Ga₂O₃ photodetectors, particularly those dominated by the photoconductive effect, inevitably face a trade-off between photoresponsivity and response speed. Common methods to mitigate this trade-off usually improve one aspect with the compromise of another. In this work, bilayer-structure Ga₂O₃ films are adopted for solar-blind photodetectors to alleviate the trade-off of photoresponsivity and response speed. The performance improvement effect of the bilayer-structure device is credited to its favorable modulation of carrier redistribution between two layers and extraction accessibility by the electrode. Through further optimization of film crystallinity by annealing, the bilayer-structure device acquires improved photoresponse performance, including a low dark current of 1.16 pA, a high photo to dark current ratio of 3.49 × 10⁷, a high R of 236.10 A W^–1, a high rejection ratio (R_254nm/R_365nm) of 1.98 × 10⁵, and a fast decay speed of 50 ms. Such excellent comprehensive performance ranks it into the top level among similar Ga₂O₃ photodetectors dominated by the photoconductive effect. This work provides a universal and facile design to mitigate the trade-off between photoresponsivity and response speed of Ga₂O₃ solar-blind photodetectors.

Keywords

bilayer-structure / carrier extraction accessibility / carrier redistribution / gallium oxide / solar-blind photodetector

References

[1] Han ZY, Song S, Liang HL, et al. High-performance IGZO/Ga₂O₃ dual-active-layer thin film transistor for deep UV detection. Appl Phys Lett. 2022; 120(26): 7.

[2] Zhang Z, Zhao X, Zhang X, et al. In-sensor reservoir computing system for latent fingerprint recognition with deep ultraviolet photo-synapses and memristor array. Nat Commun. 2022; 13(1): 6590.

[3] Yang J, Liu K, Chen X, Shen D. Recent advances in optoelectronic and microelectronic devices based on ultrawide-bandgap semiconductors. Prog Quantum Electron. 2022; 83: 100397.

[4] Yue JY, Li S, Qi S, et al. Proton irradiation effects in MOCVD grown Β-Ga₂O₃ and ϵ-Ga₂O₃ thin films. IEEE Trans Nucl Sci. 2024; 71(1): 67-71.

[5] Xia X, Li JS, Sharma R, et al. Radiation damage in the ultra-wide bandgap semiconductor Ga₂O₃. ECS J Solid State Sci Technol. 2022; 11(9): 095001.

[6] Petkov A, Cherns D, Chen WY, et al. Structural stability of β-Ga₂O₃ under ion irradiation. Appl Phys Lett. 2022; 121(17): 171903.

[7] Huang H, Yin H, Han K, et al. Robust deep UV photodetectors based on one-step-grown polycrystalline Ga₂O₃ film via pulsed laser deposition toward extreme-environment application. Adv Opt Mater. 2024; 12(24): 2400788.

[8] Goto K, Nakahata H, Murakami H, Kumagai Y. Temperature dependence of Ga₂O₃ growth by halide vapor phase epitaxy on sapphire and β-Ga₂O₃ substrates. Appl Phys Lett. 2020; 117(22): 222101.

[9] Qin Y, Dong H, Long S, et al. Enhancement-mode β-Ga₂O₃ metal-oxide-semiconductor field-effect solar-blind phototransistor with ultrahigh detectivity and photo-to-dark current ratio. IEEE Electron Device Lett. 2019; 40(5): 742-745.

[10] He H, Wu C, Hu H, et al. Bandgap engineering and oxygen vacancy defect electroactivity inhibition in highly crystalline N-alloyed Ga₂O₃ films through plasma-enhanced technology. J Phys Chem Lett. 2023; 14(28): 6444-6450.

[11] Qiao B, Zhang Z, Xie X, et al. Quenching of persistent photocurrent in an oxide UV photodetector. J Mater Chem C. 2021; 9(11): 4039-4045.

[12] Yoshikawa A, Ushida S, Iwaya M, Takeuchi T, Kamiyama S, Akasaki I. Influence of trap level on an Al_0.6Ga_0.4N/Al_0.5Ga_0.5N metal-semiconductor-metal UV photodetector. Jpn J Appl Phys. 2019; 58(SC): SCCC26.

[13] Armstrong AM, Crawford MH, Jayawardena A, Ahyi A, Dhar S. Role of self-trapped holes in the photoconductive gain of β-gallium oxide Schottky diodes. J Appl Phys. 2016; 119(10): 103102.

[14] Wang J, Xiong YQ, Ye LJ, et al. Balanced performance for beta-Ga₂O₃ solar blind photodetectors: The role of oxygen vacancies. Opt Mater. 2021; 112(8): 110808.

[15] Hou X, Zhao X, Zhang Y, et al. High-performance harsh-environment-resistant GaO_x solar-blind photodetectors via defect and doping engineering. Adv Mater. 2022; 34(1): e2106923.

[16] Sun X, Liu K, Chen X, et al. Structural and optoelectronic characteristics of β-Ga₂O₃ epitaxial films with Zn alloying and subsequent oxygen annealing. J Mater Chem C. 2023; 11(9): 3227-3234.

[17] Sun X, Liu K, Chen X, et al. Enhancement of crystalline quality and solar-blind photodetection characteristics of ε-Ga₂O₃ films by introducing Zn impurity. J Mater Chem C. 2024; 12(1): 118-124.

[18] Qin Y, Long SB, He QM, et al. Amorphous gallium oxide-based gate-tunable high-performance thin film phototransistor for solar-blind imaging. Adv Electron Mater. 2019; 5(7): 10.

[19] Zou Y, Zeng Y, Tan P, et al. Alleviating the responsivity-speed dilemma of photodetectors via opposite photogating engineering with an auxiliary light source beyond the chip. 2022 International Electron Devices Meeting (IEDM). IEEE; 2022: 19.5.1-19.5.4.

[20] Han ZY, Liang HL, Huo WX, Zhu XS, Du XL, Mei ZX. Boosted UV photodetection performance in chemically etched amorphous Ga₂O₃ thin-film transistors. Adv Opt Mater. 2020; 8(8): 8.

[21] Ding M, Hao W, Yu S, et al. Self-powered p-NiO/n-Ga₂O₃ heterojunction solar-blind photodetector with record detectivity and open circuit voltage. IEEE Electron Device Lett. 2023; 44(2): 277-280.

[22] Zhu CY, Guo XS, Dai YH, et al. Spontaneously oxidized Cu_xO/β-Ga₂O₃ p-n junction for self-powered deep-ultraviolet photodetection. IEEE Trans Electron Devices. 2023; 70(1): 167-171.

[23] Chen WC, Xu XY, Li MH, Kuang SL, Zhang KHL, Cheng QJ. A fast self-powered solar-blind ultraviolet photodetector realized by Ga₂O₃/GaN PIN heterojunction with a fully depleted active region. Adv Opt Mater. 2023; 11(8): 10.

[24] Han Y, Wang Y, Fu S, et al. Ultrahigh detectivity broad spectrum UV photodetector with rapid response speed based on p-β Ga₂O₃/n-GaN heterojunction fabricated by a reversed substitution doping method. Small. 2023; 19(16): 2206664.

[25] Zhang Q, Dong D, Zhang T, et al. Over 5 × 10³-fold enhancement of responsivity in Ga₂O₃-based solar blind photodetector via acousto-photoelectric coupling. ACS Nano. 2023; 17(23): 24033-24041.

[26] Zhang Q, Li N, Zhang T, et al. Enhanced gain and detectivity of unipolar barrier solar blind avalanche photodetector via lattice and band engineering. Nat Commun. 2023; 14(1): 418.

[27] Zhu R, Liang HL, Bai H, Zhu T, Mei ZX. Double is better: achieving an oxide solar-blind UV detector with ultrahigh detectivity and fast-refreshing capability. Appl Mater Today. 2022; 29(7): 101556.

[28] Arora K, Kumar N, Vashishtha P, Gupta G, Kumar M. Investigating the role of oxygen and related defects in the self-biased and moderate-biased performance of β-Ga₂O₃ solar-blind photodetectors. J Phys Appl Phys. 2021; 54(16): 165102.

[29] Uhlendorf J, Galazka Z, Schmidt H. Oxygen diffusion in β-Ga₂O₃ single crystals at high temperatures. Appl Phys Lett. 2021; 119(24): 242106.

[30] Wang Y, Li S, Cao J, et al. Improved response speed of β-Ga₂O₃ solar-blind photodetectors by optimizing illumination and bias. Mater Des. 2022; 221: 110917.

[31] Sheng T, Liu XZ, Qian LX, Xu B, Zhang YY. Photoelectric properties of β-Ga₂O₃ thin films annealed at different conditions. RARE Met. 2022; 41(4): 1375-1379.

[32] Li Z, Xu Y, Zhang JQ, et al. Flexible solar-blind Ga₂O₃ ultraviolet photodetectors with high responsivity and photo-to-dark current ratio. IEEE Photonics J. 2019; 11(6): 1-9.

[33] Qian LX, Wu ZH, Zhang YY, Lai PT, Liu XZ, Li YR. Ultrahigh-responsivity, rapid-recovery, solar-blind photodetector based on highly nonstoichiometric amorphous gallium oxide. ACS Photonics. 2017; 4(9): 2203-2211.

[34] Zhu WH, Xiong LX, Si JW, et al. Influence of deposition temperature on amorphous Ga₂O₃ solar-blind ultraviolet photodetector. Semicond Sci Technol. 2020; 35(5): 8.

[35] Zhang T, Guan DG, Liu NT, et al. Room temperature fabrication and post-annealing treatment of amorphous Ga₂O₃ photodetectors for deep-ultraviolet light detection. Appl Phys Express. 2022; 15(2): 5.

[36] Chen XR, Mi W, Wu JW, et al. A solar-blind photodetector based on beta-Ga₂O₃ film deposited on MgO (100) substrates by RF magnetron sputtering. Vacuum. 2020; 180(5): 109632.

[37] Liu NT, Zhang T, Chen L, et al. Fast-response amorphous Ga₂O₃ solar-blind ultraviolet photodetectors tuned by a polar AlN template. IEEE Electron Device Lett. 2022; 43(1): 68-71.

[38] Li Z, An ZY, Xu Y, et al. Improving the production of high-performance solar-blind beta-Ga₂O₃ photodetectors by controlling the growth pressure. J Mater Sci. 2019; 54(14): 10335-10345.

[39] Hu SD, Han DY, Jiang KM, et al. Influence of oxygen vacancy and metal-semiconductor contact on the device performance of amorphous gallium oxide photodetectors. Appl Phys Express. 2023; 16(2): 5.

[40] Gu K, Zhang Z, Tang K, Huang J, Liao M, Wang L. Effects of sputtering pressure and oxygen partial pressure on amorphous Ga₂O₃ film-based solar-blind ultraviolet photodetectors. Appl Surf Sci. 2022; 605: 154606.

[41] Ma X, Hou X, Tan P, et al. Fast speed Ga₂O₃ solar-blind photodetectors with low temperature process engineering. IEEE Electron Device Lett. 2023; 44(11): 1861-1864.

[42] Zhang D, Zheng W, Lin RC, Li TT, Zhang ZJ, Huang F. High quality β-Ga₂O₃ film grown with N₂O for high sensitivity solar-blind-ultraviolet photodetector with fast response speed. J Alloys Compd. 2018; 735(1): 150-154.

[43] Xu R, Ma XC, Chen YH, et al. Effect of oxygen vacancies in heteroepitaxial beta-Ga₂O₃ thin film solar blind photodetectors. Mater Sci Semicond Process. 2022; 144(1): 6.

[44] Ma YJ, Zhang XD, Feng BY, et al. Mis-cut direction of substrate effect on the photoresponse characteristic of β-Ga₂O₃ film. Vacuum. 2022; 198: 110886.

[45] Liu Z, Huang Y, Zhang C, et al. Fabrication of ϵ-Ga₂O₃ solar-blind photodetector with symmetric interdigital Schottky contacts responding to low intensity light signal. J Phys Appl Phys. 2020; 53(29): 015104.

[46] Lim N, Min J, Min JH, et al. Ultrasensitive UV-C detection based on MOCVD-grown highly crystalline ultrawide bandgap orthorhombic κ-Ga₂O₃. Appl Surf Sci. 2023; 609(6): 155350.

[47] Hu ZG, Cheng Q, Zhang T, et al. Solar-blind photodetectors fabricated on beta-Ga₂O₃ films deposited on 6 degrees off-angled sapphire substrates. J Lumin. 2023; 255(7): 119596.

[48] Sun X, Liu KW, Chen X, et al. Structural and optoelectronic characteristics of beta-Ga₂O₃ epitaxial films with Zn alloying and subsequent oxygen annealing. J Mater Chem C. 2023; 11(9): 3227-3234.

[49] Zhang X, Wang L, Wang X, et al. High-performance beta-Ga₂O₃ thickness dependent solar blind photodetector. Opt Express. 2020; 28(3): 4169-4177.

[50] Xu C, Shen L, Liu H, Pan X, Ye Z. High-quality β-Ga₂O₃ films with influence of growth temperature by pulsed laser deposition for solar-blind photodetectors. J Electron Mater. 2021; 50(4): 2043-2048.

[51] Wang Q, Chen J, Huang P, et al. Influence of growth temperature on the characteristics of β-Ga₂O₃ epitaxial films and related solar-blind photodetectors. Appl Surf Sci. 2019; 489(1): 101-109.

[52] Kumar N, Arora K, Kumar M. High performance, flexible and room temperature grown amorphous Ga₂O₃ solar-blind photodetector with amorphous indium-zinc-oxide transparent conducting electrodes. J Phys Appl Phys. 2019; 52(33): 9.

[53] Liu XZ, Liu Q, Zhao BW, Ren YX, Tao BW, Zhang WL. Comparison of beta-Ga₂O₃ thin films grown on r-plane and c-plane sapphire substrates. Vacuum. 2020; 178(6): 109435.

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