buffer layer
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2022 ◽  
Vol 141 ◽  
pp. 106423
Yangfeng Li ◽  
Xiaotao Hu ◽  
Yimeng Song ◽  
Zhaole Su ◽  
Haiqiang Jia ◽  

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 94
Pepen Arifin ◽  
Heri Sutanto ◽  
Sugianto ◽  
Agus Subagio

We report the growth of non-polar GaN and AlGaN films on Si(111) substrates by plasma-assisted metal-organic chemical vapor deposition (PA-MOCVD). Low-temperature growth of GaN or AlN was used as a buffer layer to overcome the lattice mismatch and thermal expansion coefficient between GaN and Si(111) and GaN’s poor wetting on Si(111). As grown, the buffer layer is amorphous, and it crystalizes during annealing to the growth temperature and then serves as a template for the growth of GaN or AlGaN. We used scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray diffraction (XRD) characterization to investigate the influence of the buffer layer on crystal structure, orientation, and the morphology of GaN. We found that the GaN buffer layer is superior to the AlN buffer layer. The thickness of the GaN buffer layer played a critical role in the crystal quality and plane orientation and in reducing the cracks during the growth of GaN/Si(111) layers. The optimum GaN buffer layer thickness is around 50 nm, and by using the optimized GaN buffer layer, we investigated the growth of AlGaN with varying Al compositions. The morphology of the AlGaN films is flat and homogenous, with less than 1 nm surface roughness, and has preferred orientation in a-axis.

Nanomaterials ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 165
Ruirui Jiang ◽  
Jianlong Liu ◽  
Kaiqiang Yang ◽  
Jing Zhao ◽  
Baoqing Zeng

A high emission current with relatively low operating voltage is critical for field emission cathodes in vacuum electronic devices (VEDs). This paper studied the field emission performance of single-wall carbon nanotube (SWCNT) cold cathodes prepared by screen printing with a silver paste buffer layer. The buffer layer can both enforce the adhesion between the SWCNTs and substrate, and decrease their contact resistance, so as to increase emission current. Compared with paste mixing CNTs and screen printed cathodes, the buffer layer can avoid excessive wrapping of CNTs in the silver slurry and increase effective emission area to reduce the operating voltage. The experimental results show that the turn-on field of the screen-printed SWCNT cathodes is 0.9 V/μm, which is lower than that of electrophoretic SWCNT cathodes at 2.0 V/μm. Meanwhile, the maximum emission current of the screen-printed SWCNT cathodes reaches 5.55 mA at DC mode and reaches 10.4 mA at pulse mode, which is an order magnitude higher than that of electrophoretic SWCNTs emitters. This study also shows the application insight of small or medium-power VEDs.

2022 ◽  
Vol 120 (1) ◽  
pp. 012102
Ki-Sik Im ◽  
Uiho Choi ◽  
Minho Kim ◽  
Jinseok Choi ◽  
Hyun-Seop Kim ◽  

Xuqiang Zhang ◽  
Jiangtao Chen ◽  
Jianbiao Chen ◽  
Lin Ge ◽  
Yan Li ◽  

2022 ◽  
Vol 123 ◽  
pp. 111911
Jannatun Noor Sameera ◽  
Mohammad Aminul Islam ◽  
Saiful Islam ◽  
Tasnia Hossain ◽  
M.K. Sobayel ◽  

Д.А. Кириленко ◽  
А.В. Мясоедов ◽  
А.Е. Калмыков ◽  
Л.М. Сорокин

Structural features of the interface between semipolar gallium nitride layer and buffer layer of aluminum nitride grown on a SiC/Si(001) template misoriented by an angle of 7° were studied by high-resolution transmission electron microscopy. The effect of interface morphology on the structural quality of the gallium nitride layer is revealed: faceted structure the surface of the buffer layer reduces the threading dislocations density.

Chandani Dubey ◽  
Deepak Kumar Jarwal ◽  
Hemant Kumar ◽  
Yogesh Kumar ◽  
Kavicharan Mummaneni ◽  

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