Hole emission processes from InAs quantum dots grown on p-type InAlAs/InP(001)

摘要

We report on the application of the deep level transient spectroscopy technique to the study of hole emission from the confined energy levels in quantum dots. The results are presented for self-assembled InAs quantum dots grown on p-type InAlAs barrier layers, lattice matched to an InP(001) substrate. Two deep levels, linked to the quantum dots, are detected, indicative of strong hole confinement. They were attributed respectively to hole emission from the ground state to the excited state with an activation energy of about 200 meV, and from the excited state to the InAlAs valence band edge with an activation energy of about 250 meV. A mechanism for a hole emission process occurring via an excited state is proposed.