Free growth of one-dimensional β-Ga2O3 nanostructures including nanowires, nanobelts and nanosheets using a thermal evaporation method

Abdullah, Q.N.; Yam, F.K.; Mohmood, K.H.; Hassan, Z.; Qaeed, M.A.; Bououdina, M.; Almessiere, M.A.; Al–Otaibi, Amal L.; Abdulateef, Sinan A.

doi:10.1016/j.ceramint.2016.04.165

Cited by 31 publications

(13 citation statements)

References 46 publications

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“…When these photogenerated holes drifted toward the metal/a-GaO x interface, many were trapped (process 7) because of the high density of defects in the a-GaO x thin film, leading to a large internal gain. These defects were most likely structural disorders and gallium–oxygen vacancy pairs, which can act as acceptor states in gallium oxide. , In addition, the contribution of the extrinsic transitions from the valence-band tail states and/or other defect levels to the conduction band (process 6 in Figure b) cannot be ignored. , The rejection ratio ( R 250 / R 350 ), which is defined as the ratio of the responsivity values at 250 and 350 nm, of the a-GaO x PD was 5 orders of magnitude greater than those of our samples and many other previously reported β-Ga 2 O 3 PDs. This excellent wavelength selectivity helps guarantee true, highly sensitive solar-blind photodetection.…”

Section: Results and Discussionmentioning

confidence: 50%

“…These defects were most likely structural disorders and gallium−oxygen vacancy pairs, which can act as acceptor states in gallium oxide. 13,32 In addition, the contribution of the extrinsic transitions from the valence-band tail states and/or other defect levels to the conduction band (process 6 in Figure 7b) cannot be ignored. 33,34 The rejection ratio (R 250 /R 350 ), which is defined as the ratio of the responsivity values at 250 and 350 nm, of the a-GaO x PD was 5 orders of magnitude greater than those of our samples and many other previously reported β-Ga 2 O 3 PDs.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

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Ultrahigh-Responsivity, Rapid-Recovery, Solar-Blind Photodetector Based on Highly Nonstoichiometric Amorphous Gallium Oxide

et al. 2017

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Recently, Ga2O3-based, solar-blind photodetectors (PDs) have been extensively studied for various commercial and military applications. However, to date, studies have focused only on the crystalline phases, especially β-Ga2O3, and the crystalline quality must be carefully controlled because of its strong impact on device characteristics. Based on previous reports, amorphous-semiconductor-based PDs can also be expected to exhibit excellent photodetection characteristics. In this work, amorphous gallium oxide thin films were deposited by radio frequency (RF) magnetron sputtering, and the metal–semiconductor–metal (MSM) PD was fabricated and compared with a β-Ga2O3 film prepared side-by-side as the control sample. The as-sputtered film possessed a high density of defects, including structural disorders, oxygen vacancies, and likely, dangling bonds, resulting in record-high responsivity (70.26 A/W) for a thin-film-type gallium oxide PD due to a high internal gain and the contribution of extrinsic transitions despite a relatively large dark current. The high sensitivity was further confirmed by a high 250 nm/350 nm rejection ratio exceeding 105, the specific detectivity as large as 1.26 × 1014 Jones, and a cutoff wavelength of 265.5 nm. A rapid recovery (0.10 s) rather than a strong, persistent photoconductivity was observed and attributed to effective surface recombination. Our findings contribute to a more comprehensive understanding of highly nonstoichiometric amorphous gallium oxide thin films and reveal additional pathways for the development of high-performance, solar-blind PDs that are inexpensive, large-area, and suitable for mass production.

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Section: Results and Discussionmentioning

confidence: 50%

Section: ■ Results and Discussionmentioning

confidence: 99%

Ultrahigh-Responsivity, Rapid-Recovery, Solar-Blind Photodetector Based on Highly Nonstoichiometric Amorphous Gallium Oxide

et al. 2017

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“…Then, the G values of PD-0, PD-600, PD-750, PD-900, and PD-1050 are 17.2, 17.4, 16.6, 20.0, and 268.2, respectively. In this work, the improved crystallinity of the β-Ga 2 O 3 epitaxial films grown on annealed substrates reduces the structural-disorder-related defects, which can act as acceptor states [26,27]. Next, the trapping of photogenerated holes is suppressed to some extent, as exhibited in Fig.…”

Section: Resultsmentioning

confidence: 76%

High-sensitivity β-Ga_2O_3 solar-blind photodetector on high-temperature pretreated c-plane sapphire substrate

Qian

Zhang

Lai

et al. 2017

Opt. Mater. Express

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thin film, which yielded a smoother surface and even a terraceand-step-like morphology on the substrate, resulting in improved crystallinity of the epitaxial film. Accordingly, both the dark and photo currents of β-Ga 2 O 3 metal-semiconductor-metal (MSM) PDs were increased by the enhanced carrier mobility (μ) of the more crystalline film. However, the substrate-annealing temperature must be sufficiently high to offset the rise of the dark current and thus achieve a remarkable improvement in the photodetection properties. As a result, the PD fabricated on the 1050 °C-annealed substrate exhibited extremely high sensitivity, for example, high responsivity (R) of 54.9 A/W and large specific detectivity (D*) of 3.71 × 10 14 Jones. Both parameters were increased by one order of magnitude because of the combined effects of the dramatic increase in μ and the effective reduction in defect-related recombination centers. Nevertheless, the latter also prolonged the recovery time of the PD. These findings suggest another way to develop β-Ga 2 O 3 PD with extremely high sensitivity.

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“…The RMS roughness maintained the lowest value when O 2 ratio increased to 80%, but it increased slightly when the O 2 :NH 3 ratio continued to increased from 80% to 100%. The films grown in the high O 2 ratio were mainly composed of Ga 2 O 3 , while the lattice parameter of the GaN ( a = 3.19 Å) was smaller than that of the Ga 2 O 3 ( a = 12.23 Å). , The film density was also derived from the XRR simulation, as shown in Figure c. The density of the GaO x N y film decreased with increasing oxygen concentration.…”

Section: Results and Discussionmentioning

confidence: 98%

“…The films grown in the high O 2 ratio were mainly composed of Ga 2 O 3 , while the lattice parameter of the GaN (a = 3.19 Å) was smaller than that of the Ga 2 O 3 (a = 12.23 Å). 46,47 The film density was also derived from the XRR simulation, as shown in Figure 2c. The density of the GaO x N y film decreased with increasing oxygen concentration.…”

Section: Chemistry Of Materialsmentioning

confidence: 99%

Composition and Properties Control Growth of High-Quality GaO_xN_y Film by One-Step Plasma-Enhanced Atomic Layer Deposition

Yang

et al. 2019

Chem. Mater.

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This study provided a novel method for depositing high-quality GaO x N y film by plasma-enhanced atomic layer deposition (ALD). To obtain a uniform nitrogen and oxygen composition, O2 and NH3 were led into the ALD chamber at the same time. It was found that the growth rate, composition, and optical properties of the GaO x N y film could be precisely controlled by adjusting the O2:NH3 ratio. The energy band gap was well tuned from 3.46 to 4.78 eV with increased O2 ratios. The detailed analysis of the X-ray photoelectron spectra proved the existence of Ga–O, Ga–N, and N–Ga–O bonds in prepared GaO x N y film. The surface, interface, and construction of the GaO x N y films were different with GaN and Ga2O3 films through transmission electron microscope characterization. Then a possible growth mechanism was demonstrated based on these findings. The energy band structure of all GaO x N y films deposited in this study was obtained from a detailed analysis of the valence band spectra. Importantly, the GaO x N y was found to exhibit lower leakage current and higher breakdown voltage than both GaN and Ga2O3. These findings offered a foundation and proved this material will present brilliant application prospects in photodetection, photoelectrochemical water splitting, and high-voltage devices.

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Free growth of one-dimensional β-Ga2O3 nanostructures including nanowires, nanobelts and nanosheets using a thermal evaporation method

Cited by 31 publications

References 46 publications

Ultrahigh-Responsivity, Rapid-Recovery, Solar-Blind Photodetector Based on Highly Nonstoichiometric Amorphous Gallium Oxide

Ultrahigh-Responsivity, Rapid-Recovery, Solar-Blind Photodetector Based on Highly Nonstoichiometric Amorphous Gallium Oxide

High-sensitivity β-Ga_2O_3 solar-blind photodetector on high-temperature pretreated c-plane sapphire substrate

Composition and Properties Control Growth of High-Quality GaO_xN_y Film by One-Step Plasma-Enhanced Atomic Layer Deposition

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Free growth of one-dimensional β-Ga2O3 nanostructures including nanowires, nanobelts and nanosheets using a thermal evaporation method

Cited by 31 publications

References 46 publications

Ultrahigh-Responsivity, Rapid-Recovery, Solar-Blind Photodetector Based on Highly Nonstoichiometric Amorphous Gallium Oxide

Ultrahigh-Responsivity, Rapid-Recovery, Solar-Blind Photodetector Based on Highly Nonstoichiometric Amorphous Gallium Oxide

High-sensitivity β-Ga_2O_3 solar-blind photodetector on high-temperature pretreated c-plane sapphire substrate

Composition and Properties Control Growth of High-Quality GaOxNy Film by One-Step Plasma-Enhanced Atomic Layer Deposition

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Composition and Properties Control Growth of High-Quality GaO_xN_y Film by One-Step Plasma-Enhanced Atomic Layer Deposition