INAS/GAAS QUANTUM DOTS - RADIATIVE RECOMBINATION FROM ZERO-DIMENSIONAL STATES

Nanometer-scale quantum dots are fabricated using the Stranski-Krastanov growth mode of InAs on GaAs (001). For an average coverage of four monolayers, 10(11) cm(-2) pyramidal-shaped dots (12 +/- 1 nm base along [100], 5 +/- 1 nm high) are formed as observed in plane-view and cross-section transmission electron microscopy. The quantum dots exhibit short-range order, aligning along rows in <100) directions, The three-dimensional confinement of the wave function results in ultrasharp luminescence lines (full width at half maximum <0.15 meV) from individual dots as revealed with highly spatially resolved cathodoluminescence. Even at elevated temperatures extremely sharp lines are observed, proving the delta-like zero-dimensional electronic density of states.