Determination of the strain generated in InAs/InP quantum wires: prediction of nucleation sites

7 páginas, 7 figuras.
The compositional distribution in a self-assembled InAs(P) quantum wire grown by molecular beam epitaxy on an InP(001) substrate has been determined by electron energy loss spectrum imaging. We have determined the strain and stress fields generated in and around this wire capped with a 5 nm InP layer by finite element calculations using as input the compositional map experimentally obtained. Preferential sites for nucleation of wires grown on the surface of this InP capping layer are predicted, based on chemical potential minimization, from the determined strain and stress fields on this surface. The determined preferential sites for wire nucleation agree with their experimentally measured locations. The method used in this paper, which combines electron energy loss spectroscopy, high-resolution Z contrast imaging, and elastic theory finite element calculations, is believed to be a valuable technique of wide applicability for predicting the preferential nucleation sites of epitaxial self-assembled nano-objects.
This work was supported by the SANDiE European Network of Excellence (Contract No NMP4-CT-2004-500101), the MEC NANOSELF II project (TEC2005-05781-C03), the CAM: S 0505ESP 0200 project, the Junta de Andalucia (PAI research group TEP-0120; project PAI05-TEP-00383) and by the Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, US DOE, under contract DEAC05- 00OR22725 with ORNL, managed and operated by UTBattelle, LLC.