Photoemission from InAs/GaAs quantum dots decorated with cesium adatoms

An array of non-overgrown InAs/GaAs quantum dots has been decorated with adsorbed metal atoms in situ in ultrahigh vacuum. Their electron and photoemission properties have been studied. The radical modification of the spectra of the threshold emission from the quantum dots with increasing cesium coating has been found. Two photoemission channels have been established; they are characterized by considerably different intensities, spectral locations, and widths of the selective bands. It has been shown that the decoration of the quantum dots makes it possible to control the electronic structure and quantum yield of photoemission, the nature of which is related to the excitation of the electronic states of the GaAs substrate and InAs/GaAs quantum dots.