Study of nanostructure and ethanol vapor sensing performance of WO3 thin films deposited by e-beam evaporation method under different deposition angles: application in breath analysis devices

A comparison study of InGaN/GaN multiple quantum wells grown on (111) silicon and (0001) sapphire substrates under identical conditions

“…Along with a commercial Bruker RADS software for fitting and simulation, XRD measurements conducted in a ω-2θ scan mode have been used to determine the indium content and the layer thickness in the InGaN/GaN MQW region. Reciprocal space mapping (RSM) measurements have been carried out by performing an asymmetric scan along the (10-15) direction as usual [9,[21][22][23][24][25][26][27].…”

“…Please note that detailed RSM measurements have also been performed along the (10-15) orientation [9,32] on both samples to determine the strain of the InGaN/GaN MQWs in both cases, one of the important parameters for our simulation to accurately determine the indium content and the InGaN quantum well thickness. Figure 4 shows the RSM results of Sample A and Sample B measured in an asymmetric diffraction scan along with the (10-15) orientation, demonstrating that the InGaN/GaN MQWs grown on the GaN-on-sapphire template are fully strained since all the satellite peaks from the InGaN/GaN MQW align with the vertical line which passes through the GaN peak, while it is not the case for Sample A.…”

“…The huge lattice-mismatch between either sapphire or silicon and GaN poses a great challenge in obtaining GaN with reasonably good crystal quality. GaN on sapphire suffers compressive strain due to the huge lattice mismatch of ∼16%, while GaN on silicon exhibits tensile strain as a result of the large difference in thermal expansion coefficient between GaN and Si (∼54%) in addition to the huge lattice mismatch between GaN and silicon (∼17%) [9][10][11][12][13][14]. It is wellknown that the growth of GaN on either silicon or sapphire requires a high temperature of above 1000 • C. Such a high growth temperature makes the growth of GaN on silicon more challenging, as the large thermal expansion coefficient difference between GaN and Si makes GaN on silicon suffer tensile strain, thus leading to severe cracking issues [9][10][11][12][13][14].…”

“…In recent years, great progresses have been achieved on III-nitride optoelectronic devices on silicon substrates [17][18][19]. Especially, there is an increasing demand of developing microLED based microdisplays, where Si-CMOS is normally used as an electronic driver [9][10][11][12][13][14], which requires transferring the mature growth technologies for III-nitride emitters on GaNon-sapphire to those on GaN-on-Si. However, so far, there is almost an absence in reporting a comparative study on the growth of InGaN MQWs on GaN-on-sapphire and GaN-onsilicon.…”

Utilization of the high spatial-frequency component in adaptive beam shaping by using a virtual diagonal phase grating

“…Here, the shape and flatness determines the maximum power of the ultra-high-power laser system where the fill factor to the amplifier and damage to the optics at a peak region govern the limits 10 . In addition, the performance of area laser processing, such as scribing 11 , repairing 12 , interference processing 13–15 and skin therapy 16 , is improved using a square flattop beam.…”