Wednesday, May 27, 2015

Abstract-Confined photocarrier transport in InAs pyramidal quantum dots via terahertz time-domain spectroscopy

Jorge Michael M. Presto, Elizabeth Ann P. Prieto, Karim M. Omambac, Jessica Pauline C. Afalla, Deborah Anne O. Lumantas, Arnel A. Salvador, Armando S. Somintac, Elmer S. Estacio, Kohji Yamamoto, and Masahiko Tani

We present experimental demonstration of photocarrier dynamics in InAs quantum dots (QDs) via terahertz (THz) time-domain spectroscopy (TDS) using two excitation wavelengths and observing the magnetic field polarity characteristics of the THz signal. The InAs QDs was grown using standard Stranski-Krastanow technique on semi-insulating GaAs substrate. Excitation pump at 800 nm- and 910 nm-wavelength were used to distinguish THz emission from the InAs/GaAs matrix and InAs respectively. THz-TDS at 800 nm pump revealed intense THz emission comparable to a bulk p-InAs. For 910 nm pump, the THz emission generally weakened and upon applying external magnetic field of opposite polarities, the THz time-domain plot exhibited anomalous phase-shifting. This was attributed to the possible current-surge associated with the permanent dipole in the QD.
© 2015 Optical Society of America
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