Published online by Cambridge University Press: 10 February 2011
We have determined the growth conditions which result in a narrow linewidth and room temperature emission at 1.3pm from InAs/GaAs Quantum dots (QDs). The QDs formed under these conditions are extremely uniform in size and exhibit an emission linewidth of only 25meV. Single QD layers have been incorporated into p-i-n diodes which exhibit strong electroluminescence. We have compared the efficiency of these devices with a nominally identical quantum well device. The QD based device exhibits a higher electroluminescence efficiency, especially at low current densities. At higher current densities there is a loss of efficiency due to recombination from excited states.
Operated under reverse bias, the diodes act as photo-detectors and the measured photocurrent spectrum exhibits peaks due to absorption in the ground and excited states of the QDs as well as the 2D confining layer.