High quality AlN epilayers were grown on sapphire substrates by metal organic vapor deposition and exploited as active deep ultraviolet ͑DUV͒ optoelectronic materials through the demonstration of AlN metal-semiconductor-metal ͑MSM͒ photodetectors. DUV photodetectors with peak responsivity at 200 nm with a very sharp cutoff wavelength at 207 nm have been attained. The AlN MSM photodetectors are shown to possess outstanding features that are direct attributes of the fundamental properties of AlN, including extremely low dark current, high breakdown voltage, and high DUV to visible rejection ratio and high responsivity. The results demonstrate the high promise of AlN as an active material for DUV device applications.

We report on the growth of high quality aluminum nitride (AlN) and gallium nitride (GaN) epilayers on large area (6in. diameter) silicon (111) substrates by metal organic chemical vapor deposition. We have demonstrated the feasibility of growing crack-free high quality III-nitride photonic structures and devices on 6inch Si substrates through the fabrication of blue light emitting diodes based upon nitride multiple quantum wells with high performance. The demonstration further enhances the prospects for achieving photonic integrated circuits based upon nitride-on-Si material system.

Al Ga N ∕ Ga N ∕ Al N quantum-well field-effect transistors have been demonstrated. By replacing a semi-insulating GaN epilayer with a highly resistive AlN epilayer in the device structure, parasitic conduction in the GaN epilayer, leakage current through the GaN epilayer, and the channel electrons spillover into the GaN epilayer have been completely eliminated and the drain current collapse has been reduced. The fabricated devices on sapphire substrate with 1μm gate length show a high saturation current (>1A∕mm), and excellent gate control capability with a pinch-off voltage of −6V. Even without passivation, the devices exhibit small drain current collapse (<10%) under 1μs pulse gate driving.

Micro-size light emitting diode (µLED) arrays based on III-nitride semiconductors have emerged as a promising technology for a wide range of applications. If InGaN µLED arrays can be integrated on to Si complementary metal-oxide-semiconductor (CMOS) substrates for active driving, these devices could play crucial roles in ultra-portable products such as next generation pico-projectors, as well as in emerging fields such as biophotonics and optogenetics. Here we present a demonstration of, and methods for, creating a highresolution solid-state self-emissive microdisplay based on InGaN/GaN semiconductors. An energy efficient active drive scheme is accomplished by integrating micro-emitter arrays with CMOS active matrix drivers that are flip-chip bonded together via indium metal bumps.