© The Institution of Engineering and Technology
Ga2O3 is a wide bandgap oxide semiconductor material with the bandgap value only second in magnitude to diamond among known semiconductors. As a wide-bandgap semiconductor, Ga2O3 has emerged as a new competitor to silicon carbide and III-nitrides in various applications of ultraviolet optoelectronics and high power electronics. However, almost all the devices are based on the Ga2O3 grown by molecular-beam epitaxy or chemical vapour deposition, which is time-consuming and expensive. In this work, the authors report on thin-film transistors based on wide bandgap Ga2O3 films grown by aqueous-solution spin-coating method. The morphological, optical and electrical properties of the films and devices are investigated using a range of characterisation techniques, whilst the effects of post-deposition annealing are also investigated. Both as fabricated and post-annealed Ga2O3 films are found to be very smooth and exhibit wide energy bandgaps of around 4.8 and 4.9 eV, respectively. Thin-film transistors based on the grown Ga2O3 films show n-type conductivity with the maximum electron mobility of 0.1 cm2/Vs.
References
-
-
1)
-
17. Syed, N., Zavabeti, A., Ou, J.Z., et al: ‘Printing two-dimensional gallium phosphate out of liquid metal’, Nature Commun., 2018, 9, (1), p. 3618 (doi: 10.1038/s41467-018-06124-1).
-
2)
-
6. Wu, D.S., Ou, S.L., Horng, R.H., et al: ‘Growth and characterization of Ga2O3 on sapphire substrates for UV sensor applications’, Proc. SPIE, 2012, 8263, (17), p. 826317 (doi: 10.1117/12.908768).
-
3)
-
1. Ortiz, A., Alonso, J.C., Andrade, E., et al: ‘Structural and optical characteristics of gallium oxide thin films deposited by ultrasonic spray pyrolysis’, J. Electrochem. Soc., 2001, 148, (2), pp. F26–F29 (doi: 10.1149/1.1342183).
-
4)
-
20. Tauc, J.: ‘Optical properties and electronic structure of amorphous Ge and Si’, Mater. Res. Bull., 1968, 3, (1), pp. 37–46 (doi: 10.1016/0025-5408(68)90023-8).
-
5)
-
19. Syed, N., Zavabeti, A., Mohiuddin, M., et al: ‘Sonication–assisted synthesis of gallium oxide suspensions featuring trap state absorption: test of photochemistry’, Adv. Funct. Mater., 2017, 27, (43), p. 1702295 (doi: 10.1002/adfm.201702295).
-
6)
-
3. Kokubun, Y., Miura, K., Endo, F., et al: ‘Sol-gel prepared β-Ga2O3 thin films for ultraviolet photodetectors’, Appl. Phys. Lett., 2007, 90, (3), p. 031912 (doi: 10.1063/1.2432946).
-
7)
-
2. Rebien, M., Henrion, W., Hong, M., et al: ‘Optical properties of gallium oxide thin films’, Appl. Phys. Lett., 2002, 81, (2), pp. 250–252 (doi: 10.1063/1.1491613).
-
8)
-
4. Suzuki, R., Nakagomi, S., Kokubun, Y.: ‘Solar-blind photodiodes composed of a Au Schottky contact and a β-Ga2O3 single crystal with a high resistivity cap layer’, Appl. Phys. Lett., 2011, 98, (13), p. 293 (doi: 10.1063/1.3574911).
-
9)
-
11. Fleischer, M., Meixner, H.: ‘Gallium oxide thin films: a new material for high-temperature oxygen sensors’, Sens. Actuators B. Chem., 1991, 4, (3-4), pp. 437–441 (doi: 10.1016/0925-4005(91)80148-D).
-
10)
-
10. Fleischer, M., Meixner, H.: ‘Sensing reducing gases at high-temperatures using long-term stable thin-films’. Euro. Sensors 5 Conf., Rome, Italy, 1991, , (1–3), pp. 257–261.
-
11)
-
7. Oshima, T., Okuno, T., Fujita, S.: ‘Ga2O3 thin film growth on c-plane sapphire substrates by molecular beam epitaxy for deep-ultraviolet photodetectors’, Japanese J. Appl. Phys., 2007, 46, (11), pp. 7217–7220 (doi: 10.1143/JJAP.46.7217).
-
12)
-
14. Higashiwaki, M., Sasaki, K., Kuramata, A., et al: ‘Gallium oxide (Ga2O3) metal semiconductor field-effect transistors on single-crystal β-Ga2O3 (010) substrates’, Appl. Phys. Lett., 2012, 100, (1), p. 013504 (doi: 10.1063/1.3674287).
-
13)
-
16. Berbenni, V., Milanese, C., Bruni, G., et al: ‘Thermal decomposition of gallium nitrate hydrate Ga(NO3)3 × xH2O’, J. Thermal Anal.Calorimetry, 2005, 82, (2), pp. 401–407 (doi: 10.1007/s10973-005-0909-x).
-
14)
-
9. Li, Y.B., Tolizono, T., Liao, M.Y., et al: ‘Efficient assembly of bridged β-Ga2O3 nanowires for solar-blind photodetection’, Adv. Funct. Mater., 2010, 20, (22), pp. 3972–3978 (doi: 10.1002/adfm.201001140).
-
15)
-
5. Weng, W.Y., Hsueh, T.J., Chang, S.J., et al: ‘A β-Ga2O3/GaN hetero-structured solar-blind and visible-blind dual-band photodetector’, IEEE Sens. J., 2011, 11, (6), pp. 1491–1492 (doi: 10.1109/JSEN.2010.2093880).
-
16)
-
8. Feng, P., Zhang, J.Y., Li, Q.H., et al: ‘Individual Ga2O3 nanowwires as solar-blind photodetectors’, Appl. Phys. Lett., 2006, 88, pp. 153107-1–153107-3.
-
17)
-
15. Thomas, S.R., Adamopoulos, G., Lin, Y.H., et al: ‘High electron mobility thin-film transistors based on Ga2O3 grown by atmospheric ultrasonic spray pyrolysis at low temperatures’, Appl. Phys. Lett., 2014, 105, (9), p. 092105 (doi: 10.1063/1.4894643).
-
18)
-
18. Carey, B.J., Ou, J.Z., Clark, R.M., et al: ‘Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals’, Nature Commun., 2017, 8, p. 14482 (doi: 10.1038/ncomms14482).
-
19)
-
12. Marilena, B., Cristian–Ioan, B., Hisao, S., et al: ‘β-gallium oxide as oxygen gas sensors at a high temperature’, J. Am. Ceram. Soc., 2010, 90, (9), pp. 2879–2884.
-
20)
-
13. Matsuzaki, K., Hiramatsu, H., Nomura, K., et al: ‘Growth, structure and carrier transport properties of Ga2O3, epitaxial film examined for transparent field-effect transistor’, Thin Solid Films, 2006, 496, (1), pp. 37–41 (doi: 10.1016/j.tsf.2005.08.187).
http://iet.metastore.ingenta.com/content/journals/10.1049/mnl.2018.5825
Related content
content/journals/10.1049/mnl.2018.5825
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Thin-film transistors based on wide bandgap Ga2O3 films grown by aqueous-solution spin-coating method