Size- and shape-controlled GaAs nano-whiskers grown by MOVPE:: a growth study

We have investigated the Au-catalyzed GaAs <111 > B whisker growth under low-pressure metal-organic vapour phase epitaxy conditions. By varying the growth temperature we found a maximum in the whisker growth rate at about 450-475degreesC. With increasing temperature the growth rate decreases due to competing growth at the (111) substrate surface and at the {I 101 whisker side facets, which leads to significant tapering of the whiskers. For low temperatures, the growth rate R in the In R = f (1/T)-plot results in an Arrhenius activation energy of about 67-75 kJ/mol, a value which is in agreement with activation energies reported for low-temperature planar growth of GaAs from TMG and AsH3. The Au acts as a local catalyst and as a collector of reactants, enabling a liquid-phase-epitaxy-like growth with high growth rates at the GaAs (111)B/(Au,Ga) interface. (C) 2003 Elsevier B.V. All rights reserved.