The theoretical models for calculations of band structure of wurtzite InN have been studied. Several models including nearly free electron model, pseudopotional method, Tight-Binding moethod and k·p method will be discussed. Currently most InN epitaxial films grown on GaN or sapphire substrate have wurtzite structure. To study the symmetry properties of the electron wave function in wurtzite st...

GaN ultraviolet photodetector with metal-semiconductor-metal structure is achieved by growing on a periodic trapezoid column-shape patterned sapphire substrate using metalorganic chemical vapor deposition. Under 5-V reverse bias, the photodetector fabricated on such patterned sapphire substrate exhibits a lower dark current, a higher photocurrent, and a 476 % enhancement in the maximum responsi...

A composite AlSi alloy substrate was fabricated to eliminate thermal expansion coefficient mismatch in high-power vertical light-emitting diodes (VLEDs). At 2000-mA injection current, the light output power performance of LED/sapphire, VLED/Si, and VLED/AlSi are 1458, 2465, and 2499 mW and the wall-plug efficiencies are 13.66%, 26.39%, and 28.02%, respectively. The enhanced performance is attri...

We report high-throughput growth of highly aligned single-walled carbon nanotube arrays on a-plane and r-plane sapphire substrates. This is achieved using chemical vapor deposition with ferritin as the catalyst. The nanotubes are aligned normal to the [0001] direction for growth on the a-plane sapphire. They are typically tens of micrometers long, with a narrow diameter distribution of 1.34 +/-...

Cr4+:YAG double-clad crystal fiber with an uniform 10-microm core was fabricated by using a sapphire tube as a heat capacitor to stabilize the power fluctuation of the CO2 laser in the co-drawing laser-heated pedestal growth system. The uniformity of the fiber core showed a factor of 3 improvement compared to that without the use of sapphire tube. The variation of the core diameter is within th...

Orthorhombic κ-Ga2O3, as one of the Ga2O3 polymorphs, is considered a promising ultrawide bandgap material for extreme environment devices. It more superior than conventional group III-V compound semiconductors and silicon carbides in environments demanding material/device characteristics high-voltage, high-temperature, high-pressure, high-impact, high-radiation. In this study, we demonstrate u...

We present a junction temperature analysis of GaInN/GaN quantum well (QW) light-emitting diodes (LEDs) grown on sapphire and bulk GaN substrate by micro-Raman spectroscopy. The temperature was measured up to a drive current of 250 mA (357 A/cm). We find better cooling efficiency in dies grown on GaN substrates with a thermal resistance of 75 K/W. For dies on sapphire substrates we find values a...

This letter describes a direct Cu bonding technology to there-dimensionally integrate heterogeneous dielets based on chip-on-wafer configuration. 100- $\mu \text{m}$ -cubed blue $ LEDs temporarily adhered photosensitive resin are inte...