Picosecond spectroscopy of semiconductors

Time-resolved far-infrared reflectance ofn-type GaAs

“…1 In semiconductors, time-resolved studies have been performed on electron plasmas, which were created by excitation of electrons over the band gap. 2 However, this process produces not only electrons, but holes too, which influence the observed dynamics. Additionally, the electron density cannot be kept constant during the course of the experiment, and is typically not homogeneous over the area of excitation.…”

Time-resolved absorption studies of the ZnSe/ZnSTe superlattice

“…Considering only the phase space filling effect, the induced absorption can be approximately expressed, especially for a high-energy tail, by [23][24][25] …”

Energy relaxation time of hot carriers photoexcited in InGaN

“…For THG pump measurement, the signal of transmission first decreases, and then it increases and subsequently levels off. Since the nonequilibrium reflectively spectrum is a sensitive function of carrier temperature, the reflection intensity may reverse its sign during the carrier relaxation process [3]. The observed reversed signal may be explained as the same phenomenon occurring for transmission.…”

“…Hot-carrier energy relaxation time is one such issue. Historically, many ultrafast spectroscopic investigations have focused on the cooling dynamics of carriers initially photoexcited with a photon energy above the band-gap energy E g in bulk GaAs [2][3][4] and other III-V materials. III-nitride-based semiconductors such as InGaN are highly polarized with a large LO phonon energy.…”