Selective thermal interdiffusion using patterned SiO2 masks: An alternative approach to buried CdTe/CdMgTe quantum wires

Buried CdTe/CdMgTe quantum wires with a lateral confinement potential of ab out 290 meV have been realized. Using electron beam lithography, SiO2 strip es are defined on a single quantum well sample and a subsequent 2 h anneali ng step in a Zn atmosphere results in a surprisingly strong interdiffusion between Cd and Mg atoms under the capped areas, causing a lateral modulatio n of the band gap. We obtain, e.g., for a nominal wire width of 100 nm, a l ateral subband splitting of more than 8 meV, while the extension of the squ ared exciton wave function of the ground state is reduced to about 20 nm du e to the error function-like potential shape. (C) 2001 American Institute o f Physics.