Effects of Sn doping on Ga<sub>2</sub>O<sub>3</sub>-based solar blind photodetectors

Hou Shuang; Liu Qing; Xing Zhiyang; Qian Lingxuan; Liu Xingzhao

doi:10.12086/oee.2019.190011

Article navigation > Opto-Electronic Engineering > 2019 Vol. 46 > No. 10 > 190011

Next Article Previous Article

Hou Shuang, Liu Qing, Xing Zhiyang, et al. Effects of Sn doping on Ga2O3-based solar blind photodetectors[J]. Opto-Electronic Engineering, 2019, 46(10): 190011. doi: 10.12086/oee.2019.190011

Citation:

Hou Shuang, Liu Qing, Xing Zhiyang, et al. Effects of Sn doping on Ga₂O₃-based solar blind photodetectors[J]. Opto-Electronic Engineering, 2019, 46(10): 190011. doi: 10.12086/oee.2019.190011

Effects of Sn doping on Ga₂O₃-based solar blind photodetectors

State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, Sichuan 611731, China

Fund Project: Supported by National Natural Science Foundation of China (61504022) and Fundamental Research Funds for the Central Universities (ZYGX2018J026)

More Information

Corresponding author: Qian Lingxuan, E-mail:lxqian@uestc.edu.cn

Received Date 11 January 2019

Revised Date 14 March 2019

Published Date 18 October 2019

Abstract

Abstract

In order to improve the performance of Ga₂O₃-based photodetectors (PDs), Sn-doped gallium oxide thin films were prepared on sapphire substrates by molecular beam epitaxy system. The influence of Sn doping on both Ga₂O₃ crystal structure and photoelectric properties of metal-semiconductor-metal (MSM) PDs were investigated. X-ray diffraction shows that gallium oxide films change from single crystal to polycrystalline phase when increasing the growth temperature of SnO₂. When 254 nm and 42 μW/cm² light was used, the responsivity of Sn-doped Ga₂O₃ photodetectors reached 444.51 A/W. Compared with the undoped β-Ga₂O₃ PDs, the photocurrent and responsivity of Sn-doped PDs were almost increased by two orders of magnitude, suggesting the improvement on PD performance. Spectral response shows that the cut-off wavelength of Sn-doped PDs changes from 252 nm to 274 nm by increasing Sn dose, which reveals an efficient way toward the development of the UV PDs focus on longer wavelengths. However, Sn doping also introduces impurity levels, resulting in poor time response of the MSM PDs.
- Sn doping /
- β-Ga₂O₃ /
- solar blind ultraviolet photodetector /
- responsivity

FullText(HTML)

References

[1]	王保华, 李妥妥, 郑国宪.日盲紫外探测系统研究[J].激光与光电子学进展, 2014, 51(2): 022202. doi: 10.3788/LOP51.022202 CrossRef Google Scholar Wang B H, Li T T, Zheng G X. Research of solar blind ultraviolet detection system[J]. Laser & Optoelectronics Progress, 2014, 51(2): 022202. doi: 10.3788/LOP51.022202 CrossRef Google Scholar
[2]	Giza R H, Acevedo P A, Bliss J D. Ultraviolet scene simulation for missile approach warning system testing[J]. Proceedings of SPIE, 1997, 3084: 282–291. doi: 10.1117/12.280958 CrossRef Google Scholar
[3]	Brown D M, Downey E, Kretchmer J, et al. SiC flame sensors for gas turbine control systems[J]. Solid-State Electronics, 1998, 42(5): 755–760. doi: 10.1016/S0038-1101(97)00260-8 CrossRef Google Scholar
[4]	Sang L W, Liao M Y, Sumiya M. A comprehensive review of semiconductor ultraviolet photodetectors: from thin film to one-dimensional nanostructures[J]. Sensors, 2013, 13(8): 10482–10518. doi: 10.3390/s130810482 CrossRef Google Scholar
[5]	Razeghi M. Short-wavelength solar-blind detectors-status, prospects, and markets[J]. Proceedings of the IEEE, 2002, 90(6): 1006–1014. doi: 10.1109/JPROC.2002.1021565 CrossRef Google Scholar
[6]	Dong K X, Chen D J, Zhang Y Y, et al. AlGaN solar-blind APD with low breakdown voltage[J]. Opto-Electronic Engineering, 2017, 44(4): 405–409. doi: 10.3969/j.issn.1003-501X.2017.04.004 CrossRef Google Scholar
[7]	Qian L X, Wu Z H, Zhang Y Y, et al. Ultrahigh-responsivity, rapid-recovery, solar-blind photodetector based on highly nonstoichiometric amorphous gallium oxide[J]. ACS Photonics, 2017, 4(9): 2203–2211. doi: 10.1021/acsphotonics.7b00359 CrossRef Google Scholar
[8]	Guo D Y, Liu H, Li P G, et al. Zero-power-consumption solar-blind photodetector based on β‑Ga₂O₃/NSTO heterojunction[J]. ACS Applied Materials & Interfaces, 2017, 9(2): 1619–1628. doi: 10.1021/acsami.6b13771 CrossRef Google Scholar
[9]	Qian L X, Zhang H F, Lai P T, et al. High-sensitivity β-Ga₂O₃ solar-blind photodetector on high-temperature pretreated c-plane sapphire substrate[J]. Optical Materials Express, 2017, 7(10): 3643–3653. doi: 10.1364/OME.7.003643 CrossRef Google Scholar
[10]	Oh S, Jung Y, Mastro M A, et al. Development of solar-blind photodetectors based on Si-implanted β-Ga₂O₃[J]. Optics Express, 2015, 23(22): 28300–28305. doi: 10.1364/OE.23.028300 CrossRef Google Scholar
[11]	Ravadgar P, Horng R H, Yao S D, et al. Effects of crystallinity and point defects on optoelectronic applications of β-Ga₂O₃ epilayers[J]. Optics Express, 2013, 21(21): 24599–24610. doi: 10.1364/OE.21.024599 CrossRef Google Scholar
[12]	石雄林, 刘宏宇, 侯爽, 等.表面等离子体在氧化镓基紫外探测器中的应用[J].光电工程, 2018, 45(2): 170728. doi: 10.12086/oee.2018.170728 CrossRef Google Scholar Shi X L, Liu H Y, Hou S, et al. The applications of surface plasmons in Ga₂O₃ ultraviolet photodetector[J]. Opto-Electronic Engineering, 2018, 45(2): 170728. doi: 10.12086/oee.2018.170728 CrossRef Google Scholar
[13]	Ueda N, Hosono H, Waseda R, et al. Synthesis and control of conductivity of ultraviolet transmitting β-Ga₂O₃ single crystals[J]. Applied Physics Letters, 1997, 70(26): 3561–3563. doi: 10.1063/1.119233 CrossRef Google Scholar
[14]	Matsumoto T, Aoki M, Kinoshita A, et al. Absorption and reflection of vapor grown single crystal platelets of β-Ga₂O₃[J]. Japanese Journal of Applied Physics, 1974, 13(10): 1578. doi: 10.1143/JJAP.13.1578 CrossRef Google Scholar
[15]	Kohei Sasaki, Akito Kuramata, Takekazu Masui, et al. Device-Quality β-Ga₂O₃ Epitaxial Films Fabricated by Ozone Molecular Beam Epitaxy[J]. Applied Physics Express, 2012, 5, 035502. doi: 10.1143/APEX.5.035502 CrossRef Google Scholar
[16]	Chang P C, Fan Z Y, Tseng W Y, et al. β-Ga₂O₃ nanowires: synthesis, characterization, and p-channel field-effect transistor[J]. Applied Physics Letters, 2005, 87(22): 222102. doi: 10.1063/1.2135867 CrossRef Google Scholar
[17]	Varley J B, Weber J R, Janotti A, et al. Oxygen vacancies and donor impurities in β-Ga₂O₃[J]. Applied Physics Letters, 2010, 97(14): 142106. doi: 10.1063/1.3499306 CrossRef Google Scholar
[18]	Orita M, Hiramatsu H, Ohta H, et al. Preparation of highly conductive, deep ultraviolet transparent β-Ga₂O₃ thin film at low deposition temperatures[J]. Thin Solid Films, 2002, 411(1): 134–139. doi: 10.1016/S0040-6090(02)00202-X CrossRef Google Scholar
[19]	Du X J, Li Z, Luan C N, et al. Preparation and characterization of Sn-doped β-Ga₂O₃ homoepitaxial films by MOCVD[J]. Journal of Materials Science, 2015, 50(8): 3252–3257. doi: 10.1007/s10853-015-8893-4 CrossRef Google Scholar
[20]	Usui Y, Nakauchi D, Kawano N, et al. Scintillation and optical properties of Sn-doped Ga₂O₃ single crystals[J]. Journal of Physics and Chemistry of Solids, 2018, 117: 36–41. doi: 10.1016/j.jpcs.2018.02.027 CrossRef Google Scholar
[21]	Sasaki K, Higashiwaki M, Kuramata A, et al. Growth temperature dependences of structural and electrical properties of Ga₂O₃ epitaxial films grown on β-Ga₂O₃ (010) substrates by molecular beam epitaxy[J]. Journal of Crystal Growth, 2014, 392: 30–33. doi: 10.1016/j.jcrysgro.2014.02.002 CrossRef Google Scholar
[22]	Li M Q, Yang N, Wang G G, et al. Highly preferred orientation of Ga₂O₃ films sputtered on SiC substrates for deep UV photodetector application[J]. Applied Surface Science, 2019, 471: 694–702. doi: 10.1016/j.apsusc.2018.12.045 CrossRef Google Scholar
[23]	Carrano J C, Li T, Grudowski P A, et al. Comprehensive characterization of metal-semiconductor-metal ultraviolet photodetectors fabricated on single-crystal GaN[J]. Journal of Applied Physics, 1998, 83(11): 6148–6160. doi: 10.1063/1.367484 CrossRef Google Scholar
[24]	Guo D Y, Wu Z P, Li P G, et al. Fabrication of β-Ga₂O₃ thin films and solar-blind photodetectors by laser MBE technology[J]. Optical Materials Express, 2014, 4(5): 1067–1076. doi: 10.1364/OME.4.001067 CrossRef Google Scholar

Overview

Overview

Overview: Deep ultraviolet (DUV) photodetectors with solar-blind sensitivity (cutoff wavelength shorter than 280 nm) have received much attention because their photo response can be further restricted within the DUV region only even under sun or room illuminations. Solar-blind DUV photodetectors (PDs) are important devices that can be used in various commercial and military applications, such as flame detector, missile plume sensor, and ozone holes' monitor. Currently, Si-based photodiodes are the most commonly used ultraviolet photodetector in the commercial market because of their high compatibility with the highly mature silicon processes. However, expensive and cumbersome Wood's optical filters are required because Si is sensitive to infrared, visible, and near UV lights due to its small bandgap (1.1 eV~1.3 eV). Therefore, PDs based on wide-bandgap (Eg) semiconductors are regarded as more promising alternatives. In recent years, several wide bandgap materials consisting of AlGaN, Ga₂O₃, ZnMgO, BN, and diamond were proposed for solar-blind DUV photodetectors. Among these materials, gallium oxide, which has an Eg of 4.9 eV, is intrinsically suitable for solar-blind photodetection. In the past few years, gallium oxide-based metal-semiconductor-metal (MSM) PDs have been intensively explored.

It is found that the undoped Ga₂O₃ thin films are of n-type conductivity as defects such as oxygen vacancies will be introduced during the preparation process. However, pure β-Ga₂O₃ demonstrates poor conductivity at room temperature because of low electronic mobility, hindering its practical applications based on conductance response. In order to overcome this obstacle, intentionally controlled doping becomes a very important and feasible method. Tetravalent Sn is a superb doping candidate for Ga₂O₃ because it is not only an effective n-type dopant, but also has a close ionic radius with the octahedrally coordinated Ga³⁺. Masahiro Orita group used the method of pulsed laser deposition (PLD) to grow Sn-doped Ga₂O₃ film in 2002; Azuaki Akaiwa prepared a Sn-doped Ga₂O₃ film in 2012 using the spray-assisted mist chemical vapor deposition (mist CVD) method. In 2014, Du Xuejian and others from Shandong University of China used the metal-organic chemical vapor deposition (MOCVD) method to prepare a low-resistivity Sn-doped gallium oxide homoepitaxial film. However, there are few reports on the Sn-doped gallium oxide thin films preparation of molecular beam epitaxy (MBE), which is a new and widely used film preparation technology developed with the improvement of semiconductor crystal quality requirements. In this work, we explored the growth of Sn doped Ga₂O₃ film on sapphire substrates by MBE method. Solar-blind photodetectors with MSM structure based on Sn doped Ga₂O₃ thin films were fabricated and compared with the undoped PDs. Result shows that photocurrent and responsivity almost increased by two order of magnitude for Sn doped devices, suggesting devices performance of PD can be improved by doping Sn in Ga₂O₃ films.