Control of Ge dots in dimension and position by selective epitaxial growth and their optical properties

Abstract

Control of dimension and position of Ge dots on a nanoscale is accomplished by combining Stranski–Krastanov growth mode with selective epitaxial growth technique in windows surrounded by SiO2 films on Si substrates. The dimension and the number of these dots are controlled by the size of the windows, and a single dot is grown in a window with the size of less than 300 nm. Moreover, clear phonon-resolved photoluminescence (PL) is observed from the Ge dots, reflecting the improved uniformity in their dimensions. The PL energy is found to be strongly dependent on the dot’s dimension.