tailieunhanh - Báo cáo hóa học: " The Influence of a Continuum Background on Carrier Relaxation in InAs/InGaAs Quantum Dot"

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: The Influence of a Continuum Background on Carrier Relaxation in InAs/InGaAs Quantum Dot | Nanoscale Res Lett 2007 2 509-511 DOI s11671-007-9092-2 NANO EXPRESS The Influence of a Continuum Background on Carrier Relaxation in InAs InGaAs Quantum Dot Gabriele Raino Giuseppe Visimberga Abdelmajid Salhi Maria T. Todaro Massimo De Vittorio Adriana Passaseo Roberto Cingolani Milena De Giorgi Received 11 May 2007 Accepted 27 August 2007 Published online 13 September 2007 to the authors 2007 Abstract We have investigated the ultra-fast carrier dynamics in Molecular Beam Epitaxy MBE -grown InAs InGaAs GaAs quantum dots QDs emitting at m by time resolved photoluminescence TRPL upconversion measurements with a time resolution of about 200 fs. Changing the detection energies in the spectral region from the energy of the quantum dots excitonic transition up to the barrier layer absorption edge we have found that under high excitation intensity the intrinsic electronic states are populated mainly by carriers directly captured from the barrier. Keywords Ultra fast spectroscopy Carrier relaxation Quantum dots Introduction Self-assembled semiconductor quantum dots QDs are currently deeply investigated because of their fundamental optical properties and their potential implementation as the active region of high-performance semiconductor lasers 1-3 and high-efficiency infrared detectors 4 5 . Details of carrier relaxation processes in these nanostructures are of great interest due to their immediate implications on the photoluminescence PL efficiency 6 7 strongly G. Raino El A. Salhi M. T. Todaro M. De Vittorio A. Passaseo R. Cingolani M. De Giorgi CNR - INFM Distretto Tecnologico ISUFI National Nanotechnology Laboratory via Arnesano Lecce 73100 Italy e-mail G. Visimberga Tyndall National Institute University College Cork Cork Ireland influencing the performances of the optoelectronic devices. Laser device emitting at pm as required for the second window telecommunication devices has already been achieved by means of InAs QDs capped