Electrical transport and optical model of GaAs-AlInP core-shell nanowires

A.C.E. CHIA; M. TIRADO; Y. LI; S. ZHAO; Z. MI; D. COMEDI; R.R. LAPIERRE

JOURNAL OF APPLIED PHYSICS

AMER INST PHYSICS

Lugar: New York; Año: 2012 vol. 111 p. 94319 - 94325

0021-8979

GaAs nanowires were passivated by AlInP shells grown by the Au-assisted vapor-liquid-solid method in a gas source molecular beam epitaxy system. Transmission electron microscopy confirmed a core-shell GaAs-AlInP structure. Current-voltage measurements on ensemble nanowires indicated improved carrier transport properties in the passivated nanowires as compared to their unpassivated counterpart. Similarly, individual nanowires showed improved photoluminescence intensity upon passivation. A detailed model is presented to quantify the observed improvements in nanowire conduction and luminescence in terms of a reduction in surface charge trap density and surface recombination velocity upon passivation. The model includes the effects of high-level injection, bulk recombination, and surface recombination. The model can be used as a tool for assessing various passivation methods.