Density control on self-assembling of Ge islands using carbon-alloyed strained SiGe layers

The authors show that by deposition of 0.1 ML of carbon prior to the self-assembledgrowth of Gequantum dots on a strained Si1−xGexbuffer layer a striking decrease in dot density by two orders of magnitude from about 1011to109cm−2 occurs when the Ge content of the buffer layer increases from 0% to 64%. Their results give experimental evidence for a kinetically limited growth mechanism in which Ge adatom mobility is determined by chemical interactions among C, Si, and Ge. Thus, by adjusting the Ge content of the SiGe buffer layer onto which a carbonsubmonolayer is deposited they are able to fine tune the density of the carbon-induced Gequantum dots.