We study the low-energy band structure of armchair and small-band-gap semiconducting carbon nanotubes with proximity-induced superconducting pairing when a spiral magnetic field creates strong effective spin-orbit interactions from the Zeeman term and a periodic potential from the orbital part. We find that gapless Dirac fermions can be generated by variation of a single parameter. For a small-...

A new building block for low band-gap polymers, diketopyrrolopyrrole (DPP) flanked by pyridine (PyDPP), has been synthesized via a simple synthetic route. PyDPP was polymerized with bithiophene (BT) to afford a low band-gap copolymer (PBTPyDPP) which was used as an electron donor of the active layer in polymer solar cells. The solar cell device based on PBTPyDPP exhibited a promising PCE of 4.9...

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...

The impact of post-deposition hydrogen plasma treatment (HPT) on passivation in amorphous/crystalline silicon (a-Si:H/c-Si) interfaces is investigated. Combining low temperature a-Si:H deposition and HPT, a high effective charge carrier lifetime > 8ms is achieved on c-Si<100>, which serves as model for surfaces promoting epitaxy of a-Si:H. It is shown that the passivation improvement stems from...

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 ...

Graphene oxide (GO) thin films were simply deposited on fluorine doped tin oxide (FTO) substrate via a low-voltage electrodeposition. The GO and GO thin films were characterized by Zeta Potential, X-ray diffraction, Ultraviolet-Visible spectroscopy, atomic force microscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and energy dispersive X-ray spectrosc...