Influence of different aspect ratios on the structural and electrical properties of GaN thin films grown on nanoscale-patterned sapphire substrates

Lee, Fang Wei; Ke, Wen−Cheng; Cheng, C. H.; Liao, Bo; Chen, Wei–Kuo

doi:10.1016/j.apsusc.2016.03.027

Cited by 19 publications

(11 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This can be attributed to the existence of a high intrinsic defect and several grain boundaries in the film. These defects trap and scatter moving electrons, thus decreasing their mobility in the GaN films [31,32]. Appl.…”

Section: Resultsmentioning

confidence: 99%

Optoelectronic Properties and Structural Characterization of GaN Thick Films on Different Substrates through Pulsed Laser Deposition

et al. 2017

View full text Add to dashboard Cite

Approximately 4-µm-thick GaN epitaxial films were directly grown onto a GaN/sapphire template, sapphire, Si(111), and Si(100) substrates by high-temperature pulsed laser deposition (PLD). The influence of the substrate type on the crystalline quality, surface morphology, microstructure, and stress states was investigated by X-ray diffraction (XRD), photoluminescence (PL), atomic force microscopy (AFM), transmission electron microscopy (TEM), and Raman spectroscopy. Raman scattering spectral analysis showed a compressive film stress of −0.468 GPa for the GaN/sapphire template, whereas the GaN films on sapphire, Si(111), and Si(100) exhibited a tensile stress of 0.21, 0.177, and 0.081 GPa, respectively. Comparative analysis indicated the growth of very close to stress-free GaN on the Si(100) substrate due to the highly directional energetic precursor migration on the substrate's surface and the release of stress in the nucleation of GaN films during growth by the high-temperature (1000 • C) operation of PLD. Moreover, TEM images revealed that no significant GaN meltback (Ga-Si) etching process was found in the GaN/Si sample surface. These results indicate that PLD has great potential for developing stress-free GaN templates on different substrates and using them for further application in optoelectronic devices.

show abstract

Section: Resultsmentioning

confidence: 99%

Optoelectronic Properties and Structural Characterization of GaN Thick Films on Different Substrates through Pulsed Laser Deposition

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Aspect ratio of NPSS was demonstrated to induce different growth behaviours and improve the crystal quality. 149 For NPSS with high aspect ratios (height/diameter: 2) shown in Fig. 12c, GaN growth started from both the flat-top and bottom of patterns.…”

Section: Influence Of Structural Parameters Of Pss On Led Propertiesmentioning

confidence: 96%

Application of patterned sapphire substrate for III-nitride light-emitting diodes

Zhou

Zhao

et al. 2022

Nanoscale

View full text Add to dashboard Cite

show abstract

“…A chamfer angle of 4 • has also been reported to inhibit the growth of irregular grains at the interface [30]. When the substrate is arranged into a periodic concave-convex pattern, it can effectively inhibit the development of dislocations during the epitaxial growth process and annihilate them in the early stage of formation [31][32][33]. For instance, the group of Wang Junxi of the Institute of Semiconductors of the Chinese Academy of Sciences grew an AlN buffer layer on a patterned sapphire substrate, which enabled reducing the thickness of the buffer layer and improved the IQE of the UVC LED [34].…”

Section: Immature Epitaxial Technology Of Highmentioning

confidence: 99%

Perspectives on UVC LED: Its Progress and Application

et al. 2021

View full text Add to dashboard Cite

High-quality epitaxial layers are directly related to internal quantum efficiency. The methods used to design such epitaxial layers are reviewed in this article. The ultraviolet C (UVC) light-emitting diode (LED) epitaxial layer structure exhibits electron leakage; therefore, many research groups have proposed the design of blocking layers and carrier transportation to generate high electron–hole recombination rates. This also aids in increasing the internal quantum efficiency. The cap layer, p-GaN, exhibits high absorption in deep UV radiation; thus, a small thickness is usually chosen. Flip chip design is more popular for such devices in the UV band, and the main factors for consideration are light extraction and heat transportation. However, the choice of encapsulation materials is important, because unsuitable encapsulation materials will be degraded by ultraviolet light irradiation. A suitable package design can account for light extraction and heat transportation. Finally, an atomic layer deposition Al2O3 film has been proposed as a mesa passivation layer. It can provide a low reverse current leakage. Moreover, it can help increase the quantum efficiency, enhance the moisture resistance, and improve reliability. UVC LED applications can be used in sterilization, water purification, air purification, and medical and military fields.

show abstract

Influence of different aspect ratios on the structural and electrical properties of GaN thin films grown on nanoscale-patterned sapphire substrates

Cited by 19 publications

References 27 publications

Optoelectronic Properties and Structural Characterization of GaN Thick Films on Different Substrates through Pulsed Laser Deposition

Optoelectronic Properties and Structural Characterization of GaN Thick Films on Different Substrates through Pulsed Laser Deposition

Application of patterned sapphire substrate for III-nitride light-emitting diodes

Perspectives on UVC LED: Its Progress and Application

Contact Info

Product

Resources

About