Published online by Cambridge University Press: 10 February 2011
Fifty layers of carbon-induced germanium dots, separated by 9.6 nm Si, are stacked by solid source molecular beam epitaxy. Each dot layer consists of 0.2 monolayers of pre-deposited carbon and 2.4 monolayers of post-grown Ge. These carbon-induced germanium dots are only 10 to 15 nm in diameter and 1 to 2 nm in height. Vertical alignment due to penetrating strain fields of underlying dot layers is not observed. Unlike to an identical structure without the pre-growth of carbon, a variety of advantageous aspects such as strain compensation, strongly enhanced no-phonon photoluminescence at a wavelength of around 1.3 μm and the possibility of effective waveguiding make this stack of C-induced Ge islands an attractive structure for Si based optoelectronic devices.