Electroluminescence in vertically aligned quantum dot multilayer light-emitting diodes fabricating by growth-induced islanding

A molecular beam epitaxy (MBE) growth-induced islanding process has been used to form self-organized multiple quantum dot layers, in which quantum dots from different layers are vertically aligned in columns and are electronically coupled. These structures are used as the active region in light-emitting diodes operating at room temperature. Light-emitting diodes are investigated using quantum dot columns containing single, 5 and 10 InAs quantum dots. These diodes emit light over a broad band with typical spectral linewidths of 120 nm, peaked between 1000 and 1100 nm. In addition to the quantum dot spectral feature, a spectral feature from a thin quantum well region, integral to the quantum dot formation process, is seen in the single quantum dot diode, but is eliminated in diodes with active regions containing columns of multiple quantum dots.