High-temperature annealing effect of α-Al2O3 (0001) substrates with nominal 0.25° miscut toward the a-plane $${\mathbf{ \left( {11\overline{2} 0} \right)}}$$ 11 2 ¯ 0 on ZnO films grown by MOCVD

Boukadhaba, M.A.; Fouzri, A.; Sallet, Vincent; Hassani, Saïd; Amiri, G.; Lusson, A.; Oumezzine, M.

doi:10.1007/s00339-015-9267-0

Cited by 5 publications

(6 citation statements)

References 32 publications

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“…1(f), the RMS value exhibits a monotonically decreasing trend with increasing annealing temperatures. Moreover, despite poorly defined terrace edges, a similar terrace-and-step morphology appears on the 1050 °C-annealed substrate, which is similar to previously reported results [17,19]. It was reported that there are several ordered phases on the c-plane surface of sapphire that can transform into each other under thermal treatment [19].…”

Section: Methodssupporting

confidence: 89%

“…As a consequence, the crystal quality of the β-Ga 2 O 3 epitaxial film could be degraded because the coherence degree at the interface between the epitaxial film and substrate greatly impacts defect formation, strain transfer and evolution of the film surface. Pretreatment of sapphire substrate by thermal annealing has been reported to effectively improve the crystal quality of ZnO and ZnMgO epitaxial films [16,17]. However, few studies have systematically investigated the effects of similar pretreatment on the crystal quality of β-Ga 2 O 3 epitaxial film or the performance of β-Ga 2 O 3 PD.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Methodssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

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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show abstract

“…It is well established in GaN-related material growth that atomically smooth surfaces of sapphire can be made by a high temperature annealing at ≈1100 °C which activates atomic surface migration toward atomic steps. [31] The same conditions are expected for the curved surfaces, however their restructuring on atomic scale is not affecting the macroscopic shape alteration (lens in this case). Compared with a glass heat reflow, such atomic level surface re-crystallization has more advantages in maintaining the curved shape of the lens because the major volume of material is not softened (Figure S3, Supporting Information).…”

Section: Femtosecond Laser 3d Sculpturing and Improvement Of Surface ...supporting

confidence: 56%

Free‐Form Micro‐Optics Out of Crystals: Femtosecond Laser 3D Sculpturing

Hua

Liang

Chen

et al. 2022

Adv Funct Materials

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Optical crystals are ideal materials for complex functional and durable optical components, but their good stability and hardness bring about difficulties in high‐precision machining and require surface roughness below λ/10. Femtosecond laser ablation is a widely applicable processing method indifferent to material types, but its 3D fabrication capability is limited by the accumulation of ablated debris and rough ablated surface. This work demonstrates a universal and flexible technology for the fabrication of crystalline micro‐optics with required shape and surface roughness for the most demanding optical phase control. The cavitation‐assisted ablation by a direct laser writing mode is followed by a high‐temperature treatment to remove the rough non‐crystalline layer caused by ablation. The annealing at temperatures below the melting point of the crystal reduces the roughness down to ≈2 nm without changing the structure shape. This virtue of maintaining the designed shape without change, which is impossible during thermal morphing of 3D surfaces of glasses, allows for a previously unavailable flexibility of surface finish for the most demanding optical micro‐optical elements made in this study. This universal technology with nanoscale resolution and free‐form 3D manufacturing capability is applicable for various crystals and provides a new way to fabricate micro‐/integrated‐optics and nonlinear optical elements.

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“…Before deposition of the Ga 2 O 3 thin film, the Si substrate was vacuum annealed at 650 °C for 30 min, as per the temperature profile given in Figure (a,b). This process helps the surface reconstruction of silicon, thereby suppressing the presence of irregularities caused by mechanochemical mirror polishing at the topmost surface. , The vacuum annealing might also help to obtain a smooth gallium oxide surface. , The growth temperature profile and different steps to fabricate a gallium oxide based MSM-DUV-PD are presented in Figure (a–c). Figure (a) shows the temperature profile to grow a gallium oxide thin film without a seed layer, while Figure (b) shows the temperature profile to grow a gallium oxide thin film with a high-temperature seed layer.…”

Section: Methodsmentioning

confidence: 99%

“…24,30 The vacuum annealing might also help to obtain a smooth gallium oxide surface. 31,32 The growth temperature profile and different steps to fabricate a gallium oxide based MSM-DUV-PD are presented in Figure 1(a−c). Figure 1(a) shows the temperature profile to grow a gallium oxide thin film without a seed layer, while Figure 1(b) shows the temperature profile to grow a gallium oxide thin film with a high-temperature seed layer.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Ultrahigh Performance of Self-Powered β-Ga₂O₃ Thin Film Solar-Blind Photodetector Grown on Cost-Effective Si Substrate Using High-Temperature Seed Layer

et al. 2018

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We demonstrated an ultrahigh-performance and self-powered β-Ga2O3 thin film solar-blind photodetector fabricated on a cost-effective Si substrate using a high-temperature seed layer (HSL). The polycrystalline β-Ga2O3 thin film deposited with HSL shows high performance in the solar-blind region in comparison to the amorphous Ga2O3 thin film deposited without HSL. The zero-bias digitizing sensor prototype with an HSL produces a digitized output bit with deep UV (DUV) light that exhibits a high on/off (I 254 nm/I dark) ratio of >103, a record-low dark current of 1.43 pA, and high stability and reproducibility over 100 cycles even after >2100 h. The photodetector shows minimum persistent photoconductivity and fast response in milliseconds. The photodetector yields a responsivity of 96.13 A W–1 with an external quantum efficiency of 4.76 × 104 at 5 V for 250 nm monochromatic light. The photodetector shows a high response to even a rare weak signal of DUV (44 nW/cm2). These values are the highest reported to date for a planar β-Ga2O3 thin film based photodetector despite the use of the cost-effective substrate. The asymmetric I–V curve indicates a dissimilar Schottky barrier height at the two ends of the MSM photodetector, which is discussed as the main reason for the high response even at zero bias. This work provides the guidelines to develop a β-Ga2O3-based cost-effective, self-powered, high-performance, and fast DUV photodetector that possesses a high potential for next-generation practical solar-blind photodetector application.

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High-temperature annealing effect of α-Al2O3 (0001) substrates with nominal 0.25° miscut toward the a-plane $${\mathbf{ \left( {11\overline{2} 0} \right)}}$$ 11 2 ¯ 0 on ZnO films grown by MOCVD

Cited by 5 publications

References 32 publications

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

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

Free‐Form Micro‐Optics Out of Crystals: Femtosecond Laser 3D Sculpturing

Ultrahigh Performance of Self-Powered β-Ga₂O₃ Thin Film Solar-Blind Photodetector Grown on Cost-Effective Si Substrate Using High-Temperature Seed Layer

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High-temperature annealing effect of α-Al2O3 (0001) substrates with nominal 0.25° miscut toward the a-plane $${\mathbf{ \left( {11\overline{2} 0} \right)}}$$ 11 2 ¯ 0 on ZnO films grown by MOCVD

Cited by 5 publications

References 32 publications

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

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

Free‐Form Micro‐Optics Out of Crystals: Femtosecond Laser 3D Sculpturing

Ultrahigh Performance of Self-Powered β-Ga2O3 Thin Film Solar-Blind Photodetector Grown on Cost-Effective Si Substrate Using High-Temperature Seed Layer

Contact Info

Product

Resources

About

Ultrahigh Performance of Self-Powered β-Ga₂O₃ Thin Film Solar-Blind Photodetector Grown on Cost-Effective Si Substrate Using High-Temperature Seed Layer