Transport of Charge Carriers in GaAs Nanowires by Surface Acoustic Waves

The oscillating piezoelectric field of a surface acoustic wave (SAW) extends above the surface of the piezoelectric material where it propagates. In this contribution, we demonstrate that this field can be employed to remotely transport electrons and holes in GaAs nanowires deposited on top of a piezoelectric substrate, as well as to spatially control exciton recombination on a sub-nanosecond time scale.

Fig.1: Experimental setup for measurement of acoustic transport in NWs. SAWs are electrically generated by an interdigital transducer on a LiNbO3 crystal. The NW is deposited on the path of the SAW, and electrons and holes are excited at one end of the NW.

The experiments are carried out in GaAs core-shell nanowires transferred to a LiNbO3 substrate with interditigal transducers for SAW generation. Carriers generated at one end of the NW by picosecond laser pulses are acoustically transferred to a second location several micrometers away, leading to the remote emission of sub-nanosecond light pulses synchronized with the SAW frequency (shown in original publication (1)). The dynamics of the carrier transport is investigated by spatially and time-resolved photoluminescence, and is well-reproduced by computer simulations.

 

The high-frequency contactless manipulation of carriers by SAWs opens new perspectives for applications of NWs in opto-electronic devices operating at GHz frequencies. The potential of this approach is demonstrated by the realization of a high-frequency source of anti-bunched photons based on the acoustic transport of electrons and holes in (In,Ga)As NWs.

Publication
1 Autor M. Möller , A. Hernández-Mínguez , S. Breuer , C. Pfüller , O. Brandt , M. M. de Lima Jr. , A. Cantarero , L. Geelhaar , H. Riechert , P. V. Santos
Titel

Polarized recombination of acoustically transported carriers in GaAs nanowires

Source Nanoscale Res. Lett. , 7 , 247 ( 2012 )
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M. Möller, A. Hernández-Mínguez, S. Breuer, C. Pfüller, O. Brandt, M. M. de Lima Jr., A. Cantarero, L. Geelhaar, H. Riechert, and P. V. Santos