Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Single-dot Spectroscopy of GaAs Quantum Dots Fabricated by Filling of Self-assembled Nanohole | Nanoscale Res Lett 2010 5 1633-1636 DOI s11671-010-9687-x NANO EXPRESS Single-dot Spectroscopy of GaAs Quantum Dots Fabricated by Filling of Self-assembled Nanoholes Ch. Heyn M. Klingbeil Ch. Strelow A. Stemmann S. Mendach W. Hansen Received 15 June 2010 Accepted 1 July 2010 Published online 14 July 2010 The Author s 2010. This article is published with open access at Abstract We study the optical emission of single GaAs quantum dots QDs . The QDs are fabricated by filling of nanoholes in AlGaAs and AlAs which are generated in a self-assembled fashion by local droplet etching with Al droplets. Using suitable process parameters we create either uniform QDs in partially filled deep holes or QDs with very broad size distribution in completely filled shallow holes. Micro photoluminescence measurements of single QDs of both types establish sharp excitonic peaks. We measure a fine-structure splitting in the range of 22-40 eV and no dependence on QD size. Furthermore we find a decrease in exciton-biexciton splitting with increasing QD size. Introduction Semiconductor quantum dots QDs are very attractive for advanced applications for instance in the field of quantum computing 1 and as single photon sources 2 3 for quantum cryptography. In this context the detailed knowledge of the symmetries and level-structure inside these artificial atoms and its correlation to the QD structural properties is essential. A prominent example is the excitonic fine-structure splitting FSS which is a crucial parameter for the generation of entangled photons for cryptography 3 4 . The FSS is related to the exchange interaction between electrons and holes in the strong QD Ch. Heyn M. Klingbeil Ch. Strelow A. Stemmann S. Mendach W. Hansen Institut fur Angewandte Physik und Zentrum fur Mikrostrukturforschung JungiusstraBe 11 D-20355 Hamburg Germany e-mail heyn@ confinement 5-7 and can be measured for instance by using micro photoluminescence PL .
