Sublimation sandwich route to ultralong zinc-blende ZnSe nanowires and the cathodoluminescence properties of individual nanowires

Sublimation sandwich method (SSM) was developed to fabricate ZnSe nanowires assisted by Au-catalytic vapor-liquid-solid (VLS) process. The ZnSe nanowires have zinc-blende structure and the length is ultralong, up to tens of micrometers. High-resolution transmission electron microscopic (HRTEM) investigations reveal that there are two types of nanowires: well crystalline nanowires and poor crystalline nanowires with high density of bulk defects e.g. stacking faults, dislocations and twinning defects. The cathodoluminescence spectra indicate significant difference in optical properties of these two types of nanowires. We deduce that V-zn and Zn-i are the main reason for the deep defects related green-red emission observed in well crystalline nanowires, while the bulk defects in the poor crystalline nanowires should be responsible for the deep defects related emissions centered at 515 and 604 nm. (C) 2010 Elsevier B.V. All rights reserved.