The selective deposition of compound semiconductors on single crystal silicon tip arrays produces optical quality, direct band gap materials on the silicon nanostructures. We demonstrate using the organometallic vapor phase epitaxy of GaInP that the direct band gap semiconductor nucleates selectively on the silicon tips. The structural properties of the tips ~whose radius of curvature is approx...

We demonstrated a substrate-moving vapor-liquid-solid (VLS) route for growing composition gradient ZnCdSSe alloy nanowires. Relying on temperature-selected composition deposition along their lengths, single tricolor ZnCdSSe alloy nanowires with engineerable band gap covering the entire visible range were obtained. The photometric property of these tricolor nanowires, which was determined by blu...

An experimental demonstration of a dynamic decrease of the optical band gap of bulk n-InSb induced by picosecond, midinfrared laser pulses is reported. This occurs as a result of laser heating of the quiescent electron distribution by free-carrier absorption. The hot electrons vacate low-energy states near the conductionband minimum, unblocking terminal states for two-photon absorption across t...

Due to the compatibility with the well-developed Si-based semiconductor industry, there is considerable interest in developing silicon structures with direct energy band gaps for effective sunlight harvesting. In this paper, using silicon triangles as the building block, we propose a new silicon allotrope with a direct band gap of 0.61 eV, which is dynamically, thermally and mechanically stable...

It is challenging to epitaxially grow germanene on conventional semiconductor substrate. Based on first-principles calculations, we investigate the structural and electronic properties of germanene/germanane heterostructure (HTS). The results indicate that the Dirac cone with nearly linear band dispersion of germanene maintains in the band gap of substrate. Remarkably, the band gap opened in th...

Zinc oxide (ZnO) is a promising wide band gap semiconductor. It has a direct energy band gap, Eg of 3.3eV at room temperature. ZnO can be alloyed with CdO and MgO to form the ternaries CdxZn1-xO and MgxZn1-xO, extending the direct energy band from 2.8eV to 4.0eV. Through proper doping, it also can be made transparent and conductive, piezoelectric, or ferromagnetic. ZnO based single crystal nano...

We report on the nonequilibrium dynamics of the electronic structure of the layered semiconductor Ta_{2}NiSe_{5} investigated by time- and angle-resolved photoelectron spectroscopy. We show that below the critical excitation density of F_{C}=0.2  mJ cm^{-2}, the band gap narrows transiently, while it is enhanced above F_{C}. Hartree-Fock calculations reveal that this effect can be explained by ...

Flexible optoelectronics have attracted much attention in recent years for their potential applications healthcare and wearable devices.

Doping of semiconductors by impurity atoms enabled their widespread technological application in microelectronics and optoelectronics. However, doping has proven elusive for strongly confined colloidal semiconductor nanocrystals because of the synthetic challenge of how to introduce single impurities, as well as a lack of fundamental understanding of this heavily doped limit under strong quantu...