Title :
Surface acoustic wave-driven carrier dynamics as a contact-less probe for mobilities of photogenerated carriers in undoped nanowires
Author :
Kinzel, Joerg B. ; Schulein, Florian J. R. ; Weiss, Michael ; Rudolph, Dominik ; Koblmuller, G. ; Finley, J.J. ; Streiter, Gerhard Ab ; Wixforth, Achim ; Krenner, Hubert J.
Author_Institution :
Lehrstuhl fur Experimetnalphysik 1, Univ. Augsburg, Augsburg, Germany
Abstract :
This paper presents a surface acoustic wave (SAW) technique that provides a contact-less and massively parallel probe for the intrinsic mobilities of electrons and holes in otherwise undoped surface-passivated GaAs/AlGaAs core-shell NWs. To resolve the SAW-driven carrier dynamics, stroboscopic time-correlated single photon counting (s-TCSPC) of the photoluminescence (PL) emission of individual NWs was performed. When subject to a SAW (fSAW = 194 MHz, PSAW = +5 dBm), a characteristic beating in the PL transient (blue), matching TSAW = 5.1 ns is observed. As expected, this beating shifts in time by TSAW/2 as the local acoustic phase is tuned by 180° (green). This observation is a direct fingerprint of the charge carrier dynamics and acoustic charge conveyance within the SAW-induced type-II band edge modulation. Electrons transfer from the position of the excitation laser (x0) into the energetically favourable stable points at the minimum of the conduction band. In contrast to electrons, holes remain stationary at the point of photogeneration due to their reduced mobility. TSAW/2 later these electrons are conveyed to the position of the holes giving rise to the observed beating.
Keywords :
III-V semiconductors; aluminium compounds; electron mobility; gallium arsenide; hole mobility; nanowires; photoluminescence; photon counting; semiconductor quantum wires; surface acoustic waves; Electrons transfer; GaAs-AlGaAs; SAW-induced type-II band edge modulation; acoustic charge conveyance; charge carrier dynamics; conduction band; contactless probe; electron mobility; excitation laser; hole mobility; photogenerated carrier mobility; photogeneration; photoluminescence; stroboscopic time-correlated single photon counting; surface acoustic wave-driven carrier dynamics; undoped surface-passivated core-shell nanowires; Charge carrier processes; Gallium arsenide; Nanowires; Optical surface waves; Surface acoustic waves;
Conference_Titel :
Lasers and Electro-Optics Europe (CLEO EUROPE/IQEC), 2013 Conference on and International Quantum Electronics Conference
Conference_Location :
Munich
Print_ISBN :
978-1-4799-0593-5
DOI :
10.1109/CLEOE-IQEC.2013.6800948