P1-744Kunie Ishioka, Battery Material Analysis Group, GREENE-mail：： ISHIOKA,Kunie@nims.go.jpl Transient reflectivity measurements enabled an Phonon-induced transient reflectivityFuture PlanCarrier-induced transient reflectivityConclusionKey Words: semiconductor heterointerface, coherent phononTheme underDiscussionTransient reflectivity from 10-nm thick GaP/Si(001) shows an abrupt drop at photoexcitation (t = 0). Its height is enhanced at pump photon energy of 1.4 eV due to an optical transition at the heterointerface.interface-specific excitation of electronic and phononicstates localized at buried GaP/Si heterointerface, though .Transient signal is also modulated periodically at 2 THz. Its amplitude exhibits a distinct resonant peak at 1.4 eV. The resonance behavior coincides with that of the carrier-induced response, indicating that the 2-THz mode is an interface phonon coupled strongly with interface electronic state. l To further examine the origin of the interface phonon mode, the GaP/Si heterointerface is now being examined as a function of GaP layer thickness and pump/probe light polarization. Lattice-matched GaP layers free from dislocations, stacking faults, or twins can be grown directly on an exact Si(001). The well-defined GaP/Si heterointerface has the poten- tial for application in high efficiency multi-junction solar cells as well as in monolithic integration of Ga(NAsP) lasers on Si substrates.Transient reflectivity signal of GaP/Si(001) exhibits carrier-induced response as well as a periodic modulation at 2 THz, both of which are enhanced at pump photon energy of 1.4 eV. The similar resonance behaviors indicate that the 2-THz mode is an interface phonon that is strongly coupled with an interface electronic transition.IntroductionInterface-specific Excitation of Coherent Phonons at Buried GaP/Si(001) Heterointerface
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