Effective band‐gap shrinkage in GaAs

Large Bandgap Shrinkage from Doping and Dielectric Interface in Semiconducting Carbon Nanotubes

The bandgap of a semiconductor is one of its most important electronic properties. It is often considered to be a fixed property of the semiconductor. As the dimensions of semiconductors reduce, however, many-body effects become dominant. Here, we show that doping and dielectric, two critical features of semiconductor device manufacturing, can dramatically shrink (renormalize) the bandgap. We d...

Toward soliton emission in asymmetric GaAs/AlGaAs multiple-quantum-well waveguide structures below the half-bandgap.

We report what is to our knowledge the first experimental evidence of nonlinear beam displacement in a strip-loaded GaAs/AlGaAs multiple-quantum-well waveguide with an asymmetric, nonlinear cladding. An intensity-dependent spatial displacement of ~2 mum was observed for the guided mode at a wavelength of 1.55 mum. Numerical simulations that correspond to the experiment are also presented. The d...

Evidence for effective mass reduction in GaAs/AlGaAs quantum wells

Effective Expansion: Balance between Shrinkage and Hygroscopic Expansion.

The purpose of this study was to investigate the relationship between hygroscopic expansion and polymerization shrinkage for compensation of polymerization shrinkage stresses in a restored tooth. One resin-modified glass-ionomer (RMGI) (Ketac Nano, 3M ESPE), 2 compomers (Dyract, Dentsply; Compoglass, Ivoclar), and a universal resin-based composite (Esthet•X HD, Dentsply) were tested. Volumetric...

Electroabsorption spectroscopy of effective-mass AlxGa12xAs/GaAs Fibonacci superlattices

Effective-mass Fibonacci superlattices are composed of quasiperiodic sequences of weakly coupled quantum wells in which the transfer-matrix element is significantly smaller than the confinement energy, which is significantly smaller than the confining potential. We identify several distinct classes of quasiperiodic superlattices that are distinguished by diagonal vs off-diagonal quasiperiodicit...