STM Light Emission and I(V) study of single gold nanoantenna

Hight-speed optical nanoemitters are of importance for on-chip optical data processing. A tunnel junctions can be a base for such light emitters, however such structures suffer from low quantum efficiency. One of the ways to improve efficiency of tunneling electron energy to photon generation conversion is the increase of the local density of optical states by using of optical nanoantennas. In this work, we study optoelectronic properties of single gold nanodisc with high spatial resolution. We show nonuniform distribution of electromagnetic near-fields of nanodisk, which is consistent with nanoantenna optical modes. And we demonstrate direct correlation between nanoantenna optical states and features on current-voltage characteristics of tunnel junction between metal tip and nanodisk.

STM Light Emission from p-type GaAs (110) surface

ABSTRACTSTM stimulated light emissions (STM-LE) from cleaved surfaces of GaAs(110) were investigated using a UHV-STM combined with a light detection system. Clean surfaces of Zn doped GaAs (p=5×1018) were obtained by mechanical cleavage in UHV. Light emission from the cleavage surface showed a single peak in a spectrum, which corresponds to luminescence by the conduction band to acceptor level transition in GaAs. In STM image Zn acceptors show bright tri angular-shaped contrasts, while in photon map they show dark contrasts when taken with a sample bias voltage of 2.0 V and 2.2 V at 80K. This contrast can be explained from the local band bending due to the charging effect or strain effect of the Zn acceptor.