Local Density of States in Zero-Dimensional Semiconductor Structures

Abstract
The local density of states (LDOS) within tetrahedral InAs structures, formed at the surface of InAs/GaAs(111)A, has been characterized using low-temperature scanning tunneling microscopy. The LDOS of the lowest four zero-dimensional (0D) discrete levels have been imaged in structures with a comparable size to the electron wavelength. The LDOS inside the structures is observed to be higher than that of the surrounding area at intervals of the level separation. This feature indicates the singularity of the LDOS close to the 0D resonant levels.