ABSTRACT
Ga(Al)N nanocolumns have been grown on AIN-buffered and bare Si(lll) substrates by molecular beam epitaxy. The morphology and structure is investigated by transmission electron microscopy revealing hexagonal single crystalline nanocolumns aligned along the direction. No threading dislocations are detected in the free-standing columns. The nanostructures are discussed within the framework of the specific growth mode. The fabrication of one-dimensional materials, like nanowires or nanorods, has attracted considerable attention because these materials have remarkable properties compared to the bulk material. In the field of group III-nitrides, defect-free nanostructures would offer an attractive approach to fabricate reliable high-power optoelectronic devices. Strong optical emtsston is detected from the array of nanodiscs revealing quantum confinement effects. Structure and Extended Defects Each of the columns has a relative uniform width along its entire length, which is characteristic for VLS growth behavior.
