Open Access Nano Express

Improved infrared photoluminescence characteristics from circularly ordered self-assembled Ge islands

Samaresh Das1, Kaustuv Das2, Raj Kumar Singha1, Santanu Manna1, Achintya Dhar1, Samit Kumar Ray1* and Arup Kumar Raychaudhuri2

Author Affiliations

1 Department of Physics and Meteorology, Indian Institute of Technology Kharagpur, Kharagpur 721302, India

2 DST Unit for Nanoscience, S N Bose National Centre for Basic Sciences, Block JD, Sector III, Kolkata 700098, India

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Nanoscale Research Letters 2011, 6:416  doi:10.1186/1556-276X-6-416

Published: 9 June 2011

Abstract

The formation of circularly ordered Ge-islands on Si(001) has been achieved because of nonuniform strain field around the periphery of the holes patterned by focused ion beam in combination with a self-assembled growth using molecular beam epitaxy. The photoluminescence (PL) spectra obtained from patterned areas (i.e., ordered islands) show a significant signal enhancement, which sustained till 200 K, without any vertical stacking of islands. The origin of two activation energies in temperature-dependent PL spectra of the ordered islands has been explained in detail.