title: Confined photocarrier transport in InAs pyramidal quantum dots via terahertz time-domain spectroscopy.
abstract: 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.
authors.forename: Jorge Michael M
authors.initials: JM
authors.lastname: Presto
authors.forename: Elizabeth Ann P
authors.initials: EA
authors.lastname: Prieto
authors.forename: Karim M
authors.initials: KM
authors.lastname: Omambac
authors.forename: Jessica Pauline C
authors.initials: JP
authors.lastname: Afalla
authors.forename: Deborah Anne O
authors.initials: DA
authors.lastname: Lumantas
authors.forename: Arnel A
authors.initials: AA
authors.lastname: Salvador
authors.forename: Armando S
authors.initials: AS
authors.lastname: Somintac
authors.forename: Elmer S
authors.initials: ES
authors.lastname: Estacio
authors.forename: Kohji
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Masahiko
authors.initials: M
authors.lastname: Tani