Photovoltaic Properties of p-Doped GaAs Nanowire Arrays Grown on n-Type GaAs(111)B Substrate

We report on the molecular beam epitaxy growth of Au-assisted GaAs p-type-doped NW arrays on the n-type GaAs(111)B substrate and their photovoltaic properties. The samples are grown at different substrate temperature within the range from 520 to 580 °C. It is shown that the dependence of conversion efficiency on the substrate temperature has a maximum at the substrate temperature of 550 °C. For the best sample, the conversion efficiency of 1.65% and the fill factor of 25% are obtained

Optical Study of GaAs quantum dots embedded into AlGaAs nanowires

We report on the photoluminescence characterization of GaAs quantum dots embedded into AlGaAs nano-wires. Time integrated and time resolved photoluminescence measurements from both an array and a single quantum dot/nano-wire are reported. The influence of the diameter sizes distribution is evidenced in the optical spectroscopy data together with the presence of various crystalline phases in the AlGaAs nanowires.Comment: 5 page, 5 figure

Stoichiometry and absolute atomic concentration profiles obtained by combined Rutherford backscattering spectroscopy and secondary-ion mass spectroscopy: InAs nanocrystals in Si

Abstract Rutherford backscattering spectroscopy (RBS) and secondary-ion mass spectroscopy (SIMS) were combined to achieve depth profiling calibrated in absolute atomic concentrations. This method was applied to InAs nanocrystals, grown by molecular beam epitaxy (MBE), buried in a Si matrix. By means of RBS, with its capability of accessing the buried layers, we determined the depth-integrated areal densities of As and In. These were used to calibrate the SIMS profiles with their high depth resolution and dynamic range in absolute atomic concentrations. This allowed us to identify, besides a well confined layer of stoichiometric InAs nanocrystals, significant diffusion of In and As into the Si matrix in despite of their larger atomic radii, and an excess of As due to its non-reactive deposition on Si from the excess As 4 flux during the MBE growth. On the basis of these findings, we suggest measures to optimize the MBE process for InAs/Si and similar systems