Role of vanguard counter-potential in terahertz emission due to surface currents explicated by three-dimensional ensemble Monte Carlo simulation

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dc.contributor.authorCortie, DLen_AU
dc.contributor.authorLewis, RAen_AU
dc.date.accessioned2012-03-14T23:35:01Zen_AU
dc.date.available2012-03-14T23:35:01Zen_AU
dc.date.issued2011-10-01en_AU
dc.date.statistics2012-03-15en_AU
dc.description.abstractThe discovery that short pulses of near-infrared radiation striking a semiconductor may lead to emission of radiation at terahertz frequencies paved the way for terahertz time-domain spectroscopy. Previous modeling has allowed the physical mechanisms to be understood in general terms but it has not fully explored the role of key physical parameters of the emitter material nor has it fully revealed the competing nature of the surface-field and photo-Dember effects. In this context, our purpose has been to more fully explicate the mechanisms of terahertz emission from transient currents at semiconductor surfaces and to determine the criteria for efficient emission. To achieve this purpose we employ an ensemble Monte Carlo simulation in three dimensions. To ground the calculations, we focus on a specific emitter, InAs. We separately vary distinct physical parameters to determine their specific contribution. We find that scattering as a whole has relatively little impact on the terahertz emission. The emission is found to be remarkably resistant to alterations of the dark surface potential. Decreasing the band gap leads to a strong increase in terahertz emission, as does decreasing the electron mass. Increasing the absorption dramatically influences the peak-peak intensity and peak shape. We conclude that increasing absorption is the most direct path to improve surface-current semiconductor terahertz emitters. We find for longer pump pulses that the emission is limited by a newly identified vanguard counter-potential mechanism: Electrons at the leading edge of longer laser pulses repel subsequent electrons. This discovery is the main result of our work.© 2012, American Physical Societyen_AU
dc.identifier.articlenumber15532en_AU
dc.identifier.citationCortie, D.L., Lewis, R.A. (2012). Role of vanguard counter-potential in terahertz emission due to surface currents explicated by three-dimensional ensemble Monte Carlo simulation. Physical Review B, 84(15), 15532. doi:10.1103/PhysRevB.84.155328en_AU
dc.identifier.govdoc3919en_AU
dc.identifier.issn1098-0121en_AU
dc.identifier.issue15en_AU
dc.identifier.journaltitlePhysical Review Ben_AU
dc.identifier.urihttp://dx.doi.org/10.1103/PhysRevB.84.155328en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/4095en_AU
dc.identifier.volume84en_AU
dc.language.isoenen_AU
dc.publisherAmerican Physical Societyen_AU
dc.subjectTHz rangeen_AU
dc.subjectInfrared radiationen_AU
dc.subjectMonte Carlo Methoden_AU
dc.subjectSimulationen_AU
dc.subjectScatteringen_AU
dc.subjectElectronsen_AU
dc.subjectSpectroscopyen_AU
dc.subjectAbsorptionen_AU
dc.subjectSemiconductor materialsen_AU
dc.titleRole of vanguard counter-potential in terahertz emission due to surface currents explicated by three-dimensional ensemble Monte Carlo simulationen_AU
dc.typeJournal Articleen_AU
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