We investigate doping of a single-layer graphene in the presence of electrolytic top gating. The interfacial phenomenon is modeled using a modified Poisson-Boltzmann equation for an aqueous solution of simple salt. We demonstrate both the sensitivity of graphene's doping levels to the salt concentration and the importance of quantum capacitance that arises due to the smallness of the Debye scre...

A molecular beam epitaxy grown wavelength tunable GaAs p-i homojunction interfacial work-function internal photoemission far-infrared detector is developed. The multilayer (p-ip-i. . . ! detector structures consist of 2, 5, and 10 emitter layers. Experimental results are explained in terms of the number of emitter layers and the doping concentrations of the emitter layer. A detector with 10 mul...

We have used micro-photoand cathodo-luminescence at low temperatures to study the effects of sulphur doping in InP and radial InP/InAs/InP structured nanowires. Samples with pure wurtzite crystal structure, with modulated wurtzite/zincblende crystal structure and with different radial InAs growth times were investigated. We observed a doping concentration gradient along the nanowires, the locat...

We present the first experimental study of the optical properties of HELP InGaAsP (InGaAsP grown by He-plasma-assisted molecular beam epitaxy) relevant to all-optical switching, and the first demonstration of picosecond switching using this material. We observed an optical response time of 15 ps, a nonlinear index change as large as 0.077, a sharp absorption band edge, and a small absorption ta...

The Heusler-type Fe2VAl compound is a nonmagnetic semimetal with a sharp pseudogap at the Fermi level. Doping of quaternary elements causes a large enhancement in the Seebeck coefficient, in parallel with a significant decrease in the electrical resistivity. Since the Seebeck coefficient varies systematically with the valence electron concentration (VEC), irrespective of doping elements, the ne...

P-type doping in high Al-content AlGaN alloys is a main challenge for realizing AlGaN-based deep ultraviolet optoelectronics devices. According to the first-principles calculations, Mg activation energy may be reduced so that a high hole concentration can be obtained by introducing nanoscale (AlN)5/(GaN)1 superlattice (SL) in Al0.83Ga0.17N disorder alloy. In this work, experimental evidences we...

We show that unintentional hydrogen doping of ZnO during the electrodeposition process can impact the material's carrier concentration as significantly as others have reported for intentional extrinsic doping. Mott-Schottky analyses on the natively n-type electrodeposits show a decrease in the carrier concentrations from 10(21) to 10(18) cm(-3) with increasing overpotential. A strong link exist...

In the last years there has been a renewed interest for zinc oxide semiconductor, mainly triggered by its prospects in optoelectronic applications. In particular, zinc oxide thin films are being widely used for photovoltaic applications, in which the determination of the electrical conductivity is of great importance. Being an intrinsically doped material, the quantification of its doping conce...

The effect of Al doping concentration and oxygen ambient pressure on the structural and optical properties of chemical vapor deposition-grown, Al-doped ZnO nanowires is studied. As Al doping increases, the strength of the broad visible emission band decreases and the UV emission increases, but the growth rate depends on the oxygen pressure in a complex manner. Together, these behaviors suggest ...

Two-dimensional dopant profiling using the secondary electron (SE) signal in the scanning electron microscope (SEM) is a technique gaining impulse for its ability to enable rapid and contactless low-cost diagnostics for integrated device manufacturing. The basis is doping contrast from electrical p-n junctions, which can be influenced by wet-chemical processing methods typically adopted in ULSI...