We report on structural and electrical properties of GaAs nanowires (NWs) grown by molecular beam epitaxy (MBE) on GaAs and SiO 2 substrates using Au as growth catalyst. Au-Ga particles are observed on the top of the NWs by transmission electron microscopy (TEM). In most of the observed cases, individual particles contain two Au-Ga compositions, in particular orthorhombic AuGa and β′ hexagonal Au 7Ga 2. The wires grown on GaAs are regularly shaped and tidily oriented on both (1 0 0) and (1 1 1)B substrates. TEM also reveals that the NWs have a wurtzite lattice structure. Electrical transport measurements indicate that nominally undoped NWs are weakly n-type while both Be- and Si-doped wires show p-type behaviour. The effect of the lattice structure on impurity incorporation is briefly discussed.
Physica E Low-Dimensional Systems and Nanostructures
- Pub Date:
- March 2007
- Nanoscale materials;
- Transmission electron microscopy;
- Electronic transport in nanoscale materials and structures