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

MBE growth and TEM analyses in Mn-Ge-P compounds

. Pp, 81.15.Hi Ternary MnGeP 2 thin films have been grown on GaAs substrate using MBE technique. The films prepared at 435 °C showed ferromagnetism at room temperature. TEM observation revealed a segregation of MnP tile-shaped grains. Films grown at 585 °C showed no trace of ferromagnetic secondary phases in XRD profiles and were found to show no ferromagnetic behaviors down to 77 K. This is consistent with theoretical prediction that stoichiometric MnGeP 2 is antiferromagnetic, and our previous experimental results that the MnGeP 2 layer existing at the top of ZnGeP 2 : Mn has no contribution to ferromagnetic properties of the latter

Electrical detection of picosecond acoustic pulses in vertical transport devices with nanowires

Picosecond acoustic pulses, generated in a thin aluminum transducer, are injected into semiconductor vertical transport devices consisting of core-shell GaAsP nanowires. The acoustic pulses induce current pulses in the device with amplitude ∼1 μA. The spectrum of the electrical response is sensitive to the elastic properties of the device and has a frequency cutoff at ∼10 GHz. This work shows the potential of the technique for studies the elastic properties of complex semiconductor nanodevices.Peer reviewe

Optically excited THz generation from ordered arrays of GaAs nanowires

THz generation under excitation by ultrashort optical pulses from ordered arrays of GaAs nanowires is reported. It was found that the efficiency of THz generation is determined by the geometrical parameters of nanostructures and has a resonant character. Furthermore, it is shown that the terahertz generation efficiency at optimum geometrical parameters of an array of semiconductor nanowires is greater than the corresponding value for bulk semiconductor p-InAs which is the most effective THz emitter.Peer reviewe

Thermal Penetration of Gold Nanoparticles into Silicon Dioxide

We report on an experimental study of the thermal annealing processes under air and nitrogen atmospheres of colloidal Au nanoparticles deposited onto SiO₂/Si(100) samples. It was shown that Au nanoparticles during annealing under ambient conditions could penetrate inside silicon dioxide layers forming pores at that their lengths were found to be dependent on the annealing time. The influence of oxygen on the penetration process is discussed. At the same time, the annealing of Au nanoparticles under nitrogen conditions did not result in the formation of pores