InAs quantum dots on GaAs(112)B

摘要

InAs quantum dots (QDs) were prepared by molecular beam epitaxy on GaAs(112)B substrates. Shape and size distribution of the QDs were investigated using in situ scanning tunneling microscopy as function of preparation temperature between 435 and 550?. The wetting layer is not flat but undulated in submicrometer scale in a similar way as the bare substrate. The atomic structure of the wetting layer is the same as found for the flat base of InAs QDs grown on GaAs(113)B substrates. The shape of the QDs is given by {110}, (111)B, and {143}B bounding facets and a round vicinal (001) region. Unexpectedly, the number density increases and the size distribution sharpens, when the growth temperature is increased from 435 to 470℃, which is attributed to lattice defects incorporated into the QDs during growth at 435℃.