Hoe Hark Tan

Polarization and temperature dependence of photoluminescence from zincblende and wurtzite InP nanowires

A.M., L.V.T., T.B.H., H.E.J., L.M.S., and J.M.Y.-R. acknowledge support from the Institute for Nanoscale Science and Technology of the University of Cincinnati and the National Science Foundation through Grant Nos. EEC/NUE 0532495 and ECCS 0701703. The Australian authors acknowledge support from the Australian Research Council. Y.K. acknowledges support by the Korean Science and Engineering Foundation KOSEF through Grant No. F01- 2007-000-10087-0.

Temperature dependence of photoluminescence from single core-shell GaAs–AlGaAs nanowires

This work was supported by the University of Cincinnati. Australian authors gratefully acknowledge the financial support from the Australian Research Council.

Carrier Dynamics and Quantum Confinement in type II ZB-WZ InP Nanowire Homostructures

We use time-resolved photoluminescence from single InP nanowires containing both wurtzite (WZ) and zincblende (ZB) crystalline phases to measure the carrier dynamics of quantum confined excitons in a type-II homostructure. The observed recombination lifetime increases by nearly 2 orders of magnitude from 170 ps for excitons above the conduction and valence band barriers to more than 8400 ps for electrons and holes that are strongly confined in quantum wells defined by monolayer-scale ZB sections in a predominantly WZ nanowire. A simple computational model, guided by detailed high-resolution transmission electron microscopy measurements from a single nanowire, demonstrates that the dynamics are consistent with the calculated distribution of confined states for the electrons and holes.

Polarization-sensitive terahertz detection by multicontact photoconductive receivers

The Australian authors would like to acknowledge the financial support of the Australian Research Council.

Multipulse operation of a Ti:sapphire laser mode locked by an ion-implanted semiconductor saturable-absorber mirror

We show results obtained from a semiconductor saturable-absorber mirror mode-locked Ti:sapphire soliton laser that was operated in the multiple-pulse regime. Double, triple, and quadruple pulses were observed when the dispersion was decreased below a critical value. The pulse pairs and triplets were either widely separated or closely coupled, and spectra that resembled those of constant as well as rotating phase differences between pulses were observed. We explain our observations in the framework of the generalized complex Ginzburg‐ Landau equation as the master equation of the laser.

Structural characteristics of GaSb∕GaAs nanowire heterostructures grown by metal-organic chemical vapor deposition

Highly lattice mismatched (7.8%) GaAs/GaSb nanowire heterostructures were grown by metal-organic chemical vapor deposition and their detailed structural characteristics were determined by electron microscopy. The facts that (i) no defects have been found in GaSb and its interfaces with GaAs and (ii) the lattice mismatch between GaSb/GaAs was fully relaxed suggest that the growth of GaSb nanowires is purely governed by the thermodynamics. The authors believe that the low growth rate of GaSb nanowires leads to the equilibrium growth. (c) 2006 American Institute of Physics.

Nearly intrinsic exciton lifetimes in single twin-free GaAs/AlGaAs core-shell nanowire heterostructures

S.P., M.A.F., H.E.J., L.M.S., and J.M.Y.-R. acknowledge the financial support of the University of Cincinnati and the National Science Foundation through Grant Nos. EEC/NUE- 0532495, ECCS-0701703, and DMR/MWN-0806700. H.J.J., Q.G., H.H.T., C.J., X.Z., and J.Z. acknowledge support from the Australian Research Council and the Australian National Fabrication Facility.

Influence of surface passivation on ultrafast carrier dynamics and terahertz radiation generation in GaAs

The authors would like to acknowledge support from the EPSRC UK, the Royal Society UK, and the ARC Australia for this work.

The effect of V/III ratio and catalyst particle size on the crystal structure and optical properties of InP nanowires

InP nanowires were grown on 111B InP substrates by metal-organic chemical vapour deposition in the presence of colloidal gold particles as catalysts. Transmission electron microscopy and photoluminescence measurements were carried out to investigate the effects of V/III ratio and nanowire diameter on structural and optical properties. Results show that InP nanowires grow preferably in the wurtzite crystal structure than the zinc blende crystal structure with increasing V/III ratio or decreasing diameter. Additionally, time-resolved photoluminescence (TRPL) studies have revealed that wurtzite nanowires show longer recombination lifetimes of approximately 2500 ps with notably higher quantum efficiencies.

Super Deformability and Young’s Modulus of GaAs Nanowires

A significant size effect on the mechanical properties of GaAs nanowires (NWs) is reported. A remarkable elastic strain of approximate to 11% for NWs with diameters of 50-150 nm and obvious plastic deformation in NWs with diameters <= 25 nm are revealed. The Youngs modulus of the NWs can be more than double that of bulk GaAs.