Beschreibung:
AbstractSingle vertically stacked pairs of InP quantum dots (QDs) with different interdot barrier width are investigated using microphotoluminescence, photoluminescence excitation spectroscopy and time‐resolved techniques. The results indicate unidirectional carrier tunneling to be the main coupling mechanism between the two layers containing QDs with intentionally different size. The coupling is changing from electron–hole tunneling to electron tunneling and finally vanishing tunneling with increasing barrier size.magnified imageTwo QDs of different size form an asymmetric QD molecule with different ground state energies of the composing single QDs. Carriers can tunnel from the small dot to the large dot depending on the interdot spacer thickness dsp.