Deep-Ultraviolet Photodetection Using Single-Crystalline β-Ga2O3/NiO Heterojunctions

Embargo End Date
2020-08-29

Type
Article

Authors
Li, Kuang-Hui
Alfaraj, Nasir
Kang, Chun Hong
Braic, Laurentiu
Hedhili, Mohamed N.
Guo, Zaibing
Ng, Tien Khee
Ooi, Boon S.

KAUST Department
Thin Films & Characterization
Surface Science

KAUST Grant Number
BAS/1/1614-01-01

Online Publication Date
2019-08-29

Print Publication Date
2019-09-25

Date
2019-08-29

Abstract
In recent years, β-Ga2O3/NiO heterojunction diodes have been studied, but reports in the literature lack an investigation of an epitaxial growth process of high-quality single-crystalline β-Ga2O3/NiO thin films via electron microscopy analysis and the fabrication and characterization of an optoelectronic device based on the resulting heterojunction stack. This work investigates the thin-film growth of a heterostructure stack comprising n-type β-Ga2O3 and p-type cubic NiO layers grown consecutively on c-plane sapphire using pulsed laser deposition, as well as the fabrication of solar-blind ultraviolet-C photodetectors based on the resulting p-n junction heterodiodes. Several characterization techniques were employed to investigate the heterostructure, including X-ray crystallography, ion beam analysis, and high-resolution electron microscopy imaging. X-ray diffraction analysis confirmed the single-crystalline nature of the grown monoclinic and cubic (2̅01) β-Ga2O3 and (111) NiO films, respectively, whereas electron microscopy analysis confirmed the sharp layer transitions and high interface qualities in the NiO/β-Ga2O3/sapphire double-heterostructure stack. The photodetectors exhibited a peak spectral responsivity of 415 mA/W at 7 V reverse-bias voltage for a 260 nm incident-light wavelength and 46.5 pW/μm2 illuminating power density. Furthermore, we also determined the band offset parameters at the thermodynamically stable heterointerface between NiO and β-Ga2O3 using high-resolution X-ray photoelectron spectroscopy. The valence and conduction band offsets values were found to be 1.15 ± 0.10 and 0.19 ± 0.10 eV, respectively, with a type-I energy band alignment.

Citation
Li, K.-H., Alfaraj, N., Kang, C. H., Braic, L., Hedhili, M. N., Guo, Z., … Ooi, B. S. (2019). Deep-Ultraviolet Photodetection Using Single-Crystalline β-Ga2O3/NiO Heterojunctions. ACS Applied Materials & Interfaces, 11(38), 35095–35104. doi:10.1021/acsami.9b10626

Acknowledgements
The authors acknowledge receipt of KAUST baseline funding, BAS/1/1614-01-01.

Publisher
American Chemical Society (ACS)

Journal
ACS Applied Materials & Interfaces

DOI
10.1021/acsami.9b10626

Additional Links
https://pubs.acs.org/doi/10.1021/acsami.9b10626

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