Luminescence Following Highly Localized Hole Carrier Injection into InGaAs Quantum Dots

Tunneling current induced luminescence (TCIL) spectra of capped InGaAs quantum dots (QD) are presented. In contrast to the inhomogeneously broadened photoluminescence, the TCIL shows sharp excitonic lines of typical widths of 1.5–2 meV. Due to the high spatial resolution afforded by using a scanning tunneling microscope tip, TCIL spectra have been measured at various spatial locations on a capped QD sample. It is proposed that the measured luminescence spectra are of a single QD, a pair of coupled QDs and an ensemble of QDs.