Group III-Nitride heterostructures: From materials research to devices

Group III-nitride based heterostructures are of rapidly growing importance for the fabrication of short-wavelength light-emitting devices as well as for high-power high-frequency field effect transistors. Design and modeling of high-performance devices requires the precise knowledge of basic (AlGaIn)N material parameters. First, the composition dependence of the AlGaN and InGaN band gap energy will be addressed. Second, available data on the band offsets between GaN and AlGaN as well as GaN and InGaN will be discussed, which are important parameters for the design of GaN/AlGaN and InGaN/GaN hetero- and quantum well (QW) structures. Next, the effect of built-in strain and resulting piezoelectric fields on the luminescence properties of InGaN/GaN quantum wells will be addressed, including implications for an optimization of the InGaN QW width for light-emitting diode (LED) applications. Finally, results on GaN/InGaN/AlGaN QW LEDs emitting in the violet spectral region will be presented.