Low temperature tool for photoluminescence mapping with submicron resolution

We have developed a local probe technique in order to realize photoluminesc ence maps with submicron resolution at temperatures as low as 25 K. To this end a closed cycle He cryostat has been modified in order to damp mechanic al vibrations to avoid spatial resolution losses. Both the optical laser pu mp and the collected signal are fiber-optic coupled. Photoluminescence maps are provided by a motorized X-Y translation stage that scans the microscop e objective over the sample surface. The overall resolution of the micropho toluminescence (mu -PL) system is similar to 500 nm, by considering the con tributions of the laser focused spot size (lambda =325 nm), the cryostat vi brations, and the motorized stage resolution. The system is described and t wo low temperature mu -PL experiments on quantum wires and quantum dot nano structures are presented and discussed. (C) 2001 American Institute of Phys ics.