The c-axis and a-axis orientations in InN grown directly on (0001) sapphire substrate by rf-MBE

2003 ◽  
Author(s):  
T. Yamaguchi ◽  
Y. Saito ◽  
K. Kano ◽  
I. Araki ◽  
N. Teraguchi ◽  
...  
Keyword(s):  
Sapphire Substrate

Preliminary study of a new type of gas microstrip chamber on a sapphire substrate

1995 ◽  
Vol 354 (2-3) ◽  
pp. 309-317 ◽  
Author(s):  
Yu.L. Grishkin ◽  
A.N. Martemyanov ◽  
A. Akindinov ◽  
M.M. Chumakov ◽  
O.I. Pogorelko ◽  
...  
Keyword(s):  
Sapphire Substrate ◽  
New Type ◽  
Preliminary Study

scholarly journals Temperature Dependence of Stress and Optical Properties in AlN Films Grown by MOCVD

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 698
Author(s):  
Wenwang Wei ◽  
Yi Peng ◽  
Jiabin Wang ◽  
Muhammad Farooq Saleem ◽  
Wen Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Compressive Stress ◽  
Sapphire Substrate ◽  
Light Transmission ◽  
Chemical Vapor ◽  
Biaxial Stress ◽  
X Ray Diffraction ◽  
Patterned Sapphire Substrate ◽  
Transmission Electron ◽  
Nano Patterning

AlN epilayers were grown on a 2-inch [0001] conventional flat sapphire substrate (CSS) and a nano-patterned sapphire substrate (NPSS) by metalorganic chemical vapor deposition. In this work, the effect of the substrate template and temperature on stress and optical properties of AlN films has been studied by using Raman spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-visible spectrophotometer and spectroscopic ellipsometry (SE). The AlN on NPSS exhibits lower compressive stress and strain values. The biaxial stress decreases from 1.59 to 0.60 GPa for AlN on CSS and from 0.90 to 0.38 GPa for AlN on NPSS sample in the temperature range 80–300 K, which shows compressive stress. According to the TEM data, the stress varies from tensile on the interface to compressive on the surface. It can be deduced that the nano-holes provide more channels for stress relaxation. Nano-patterning leads to a lower degree of disorder and stress/strain relaxes by the formation of the nano-hole structure between the interface of AlN epilayers and the substrate. The low crystal disorder and defects in the AlN on NPSS is confirmed by the small Urbach energy values. The variation in bandgap (Eg) and optical constants (n, k) with temperature are discussed in detail. Nano-patterning leads to poor light transmission due to light scattering, coupling, and trapping in nano-holes.

Determination of scattering mechanisms in AlInGaN/GaN heterostructures grown on sapphire substrate

2021 ◽  
Vol 864 ◽  
pp. 158895
Author(s):  
F. Sonmez ◽  
E. Arslan ◽  
S. Ardali ◽  
E. Tiras ◽  
E. Ozbay
Keyword(s):  
Sapphire Substrate ◽  
Scattering Mechanisms

scholarly journals Using Amorphous CoB Alloy as Transducer to Detect Acoustic Propagation and Heat Transport at Interface

2021 ◽  
Vol 11 (11) ◽  
pp. 5155
Author(s):  
Liu Jian ◽  
Gyung-Min Choi
Keyword(s):  
Heat Transport ◽  
Sapphire Substrate ◽  
Intermediate Layer ◽  
Thermal Conductance ◽  
Acoustic Oscillation ◽  
Acoustic Propagation ◽  
Acoustic Oscillations ◽  
Interfacial Coupling ◽  
Soft Layer ◽  
Substrate Interface

Acoustic oscillation provides useful information regarding the interfacial coupling between metal transducer layers and substrate materials. The interfacial coupling can be significantly reduced by a mechanically soft layer between the transducer and substrate. However, preserving a thin, soft layer at the interface during fabrication is often challenging. In this study, we demonstrate that an amorphous CoB alloy on top of a sapphire substrate can substantially amplify acoustic oscillations. By analyzing the attenuation of acoustic oscillations, we show that a thin, soft layer with a thickness of >2 ± 1 Å exists at the interface. The intermediate layer at the interface is further verified by investigating heat transport. By analyzing the slow decrease of the temperature of the transducer layer, we determine a thermal conductance of 35 ± 5 MW m−2 K−1 at the transducer/substrate interface. This low value supports the existence of a thin, soft layer at the interface. Our results demonstrate that an amorphous metal with B alloying effectively preserves the soft nature at the interface and detects the acoustic propagation and heat transport across it.

Small GaN-based light-emitting diodes with a single electrode pad fabricated on a sapphire substrate

2008 ◽  
Vol 23 (4) ◽  
pp. 045013 ◽  
Author(s):  
Y C Lee ◽  
C E Lee ◽  
T C Lu ◽  
H C Kuo ◽  
S C Wang
Keyword(s):  
Sapphire Substrate ◽  
Light Emitting Diodes ◽  
Light Emitting
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