Temperature-dependent photoluminescence of ZnSe/ZnS quantum dots fabricated under the Stranski-Krastanov mode

Self-assembled ZnSe/ZnS quantum dots (QDs) have been grown in the Stranski-Krastanov (S-K) mode using a metalorganic chemical vapor deposition technique under the atomic-layer epitaxy mode. Atomic-force-microscopy measurements on the uncapped ZnSe/ZnS QDs reveal that lens-shaped ZnSe QDs are formed after 1-2 monolayer ZnSe is deposited. The ZnSe QDs are estimated 1-2 nm in height and 25-35 nm in radius. The temperature-dependent behavior of confined carriers in the ZnSe QDs has been investigated through photoluminescence (PL) measurements. PL spectra show a substantial PL linewidth narrowing accompanied by a large redshift of the emission peak energy with increasing temperature. This unusual temperature-dependent behavior is interpreted as the dot-to-dot carrier transfer through the wetting layer, which is common to QDs grown in the S-K mode. (C) 2003 American Institute of Physics.