tailieunhanh - Báo cáo hóa học: " Optical Properties of GaAs Quantum Dots Fabricated by Filling of Self-Assembled Nanoholes"

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: Optical Properties of GaAs Quantum Dots Fabricated by Filling of Self-Assembled Nanoholes | Nanoscale Res Lett 2010 5 576-580 DOI S11671-009-9507-3 NANO EXPRESS Optical Properties of GaAs Quantum Dots Fabricated by Filling of Self-Assembled Nanoholes Ch. Heyn A. Stemmann T. Koppen Ch. Strelow T. Kipp M. Grave S. Mendach W. Hansen Received 4 November 2009 Accepted 9 December 2009 Published online 25 December 2009 The Author s 2009. This article is published with open access at Abstract Experimental results of the local droplet etching technique for the self-assembled formation of nanoholes and quantum rings on semiconductor surfaces are discussed. Dependent on the sample design and the process parameters filling of nanoholes in AlGaAs generates strain-free GaAs quantum dots with either broadband optical emission or sharp photoluminescence PL lines. Broadband emission is found for samples with completely filled flat holes which have a very broad depth distribution. On the other hand partly filling of deep holes yield highly uniform quantum dots with very sharp PL lines. Keywords Quantum dots Molecular beam epitaxy Droplet etching Photoluminescence Atomic force microscopy Introduction Crystalline semiconductor quantum dots QDs can be regarded as artificial atomic-like entities which intrigue from a fundamental point of view 1 . But semiconductor QDs are also very attractive for device applications where QDs turned out to be superior to bulk material. This has been demonstrated for instance by the first QD-based laser that exhibits a lower threshold current density compared to QW lasers 2 . Further advanced applications for QDs are Ch. Heyn El A. Stemmann T. Koppen Ch. Strelow T. Kipp M. Grave S. Mendach W. Hansen Institut fur Angewandte Physik und Zentrum fur Mikrostrukturforschung JungiusstraBe 11 20355 Hamburg Germany e-mail heyn@ proposed such as qubits in quantum computing 3 or single-photon sources in quantum cryptography 4 5 . Quantum dot fabrication techniques that are based on self-assembling mechanisms