Growth of wurtzite InP/GaP core-shell nanowires by metal-organic molecular beam epitaxy

We report on the selective area vapor-liquid-solid (SA-VLS) growth of InP/GaP core shell nano-wires (NWs) by metal organic molecular beam epitaxy. Wurtzite crystal structure of the core InP was transferred to the GaP shell through layer by layer radial growth which eliminated bending of the NWs in random directions. Low growth temperature restricted surface segregation and kept the shell free from indium. Strain in the GaP shell was partially relaxed through formation of periodic misfit dislocations. From the periodicity of Moiré fringes and splitting of the fast-Fourier-transform of the transmission electron micrographs, the radial and axial strain were determined as 4.5% and 6.2%, respectively.