Ultrashort pulse lasers are evidencing their benefits in the processing of transparent materials. Sapphire is one most attractive engineering materials today. It hard and, therefore, difficult to machine mechanically required shape. Laser dicing promising techniques for sapphire separation. Two-pulse two-colour irradiation was applied initiate free-shape cutting material. Two collinear laser be...

High quality wafer-scale free-standing WS2 grown by van der Waals rheotaxy (vdWR) using Ni as a texture promoting layer is reported. The microstructure of vdWR grown WS2 was significantly modified from mixture of crystallites with their c-axes both parallel to (type I) and perpendicular to (type II) the substrate to large type II crystallites. Wafer-scale transfer of vdWR grown WS2 onto differe...

Massive aligned carbon nanotubes hold great potential but also face significant integration/assembly challenges for future beyond-silicon nanoelectronics. We report a wafer-scale processing of aligned nanotube devices and integrated circuits, including progress on essential technological components such as wafer-scale synthesis of aligned nanotubes, wafer-scale transfer of nanotubes to silicon ...

A method of measuring the precise temperature distribution of GaN-based light-emitting diodes (LEDs) by quantitative infrared micro-thermography is reported. To reduce the calibration error, the same measuring conditions were used for both calibration and thermal imaging; calibration was conducted on a highly emissive black-painted area on a dummy sapphire wafer loaded near the LED wafer on a t...

High-temperature annealing of sputtered AlN (Sp-AlN) using a face-to-face configuration is novel technique that has attracted considerable attention because it can reduce the threading dislocation density Sp-AlN to 107 cm−2. However, drawbacks such as cracking, residual stress, and wafer curvature remain high temperature 1700 °C. We previously developed thermal strain analysis model uses an ela...

Using the example of epitaxial lateral overgrowth AlN on trench-patterned AlN/sapphire templates, impact introducing a high-temperature annealing step into process chain is investigated. Covering open surfaces sapphire trench sidewalls with thin layer found to be necessary preserve shape during annealing. Both influence temperature and duration are To avoid deformation interface annealing, or m...

Unintentionally formed nanocrystalline graphene (nc-G) can act as a useful seed for the large-area synthesis of a hexagonal boron nitride (h-BN) thin film with an atomically flat surface that is comparable to that of exfoliated single-crystal h-BN. A wafer-scale dielectric h-BN thin film was successfully synthesized on a bare sapphire substrate by assistance of nc-G, which prevented structural ...

Using a combinatorial approach, Cr, Al and C have been deposited onto sapphire wafer substrates by High Power Impulse Magnetron Sputtering (HiPIMS) and DC magnetron sputtering. X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and X-ray diffraction were employed to determine the composition and microstructure of the coatings and confirm the presence of the Cr2AlC MAX phase within ...

Liquid-immersion nanosecond-pulsed laser micromachining is introduced as an efficient way for device isolation and rapid prototyping on GaN-on-sapphire wafer. Using deionized water as an ambient medium for laser micromachining, smooth trenches that are free from redeposition can be formed in the GaN layer. Coupled with the large difference between the ablation thresholds and ultraviolet absorpt...