Ultrafast Time Dependence of Surface Photo-Voltage Effect onp-Type GaAs(100) Surface

Dynamics of photo‐excited carriers on GaAs(100) surface studied by ultrafast time‐resolved photoemission

“…Therefore, the recombination is dominated by the photo-excited electron dynamics in the n-type GaAs. In our previous reports [4,5], it was supposed that the fast decay component is due to the hot electron relaxation in the conduction band because Shank et al reported that the hot carrier distribution approaches to the lattice temperature with a similar time constant of approximately 4 ps [10]. The present experiment shows that the lifetime of the fast decay component was hardly affected by the dopant level, laser power, and sample temperature which change the barrier height of the surface potential and the depth of the band bending region, in other words, the space charge region (SCR).…”

“…In our previous papers [4,5], the ultrafast photoexcited carrier dynamics on the n-type and p-type GaAs(100) surfaces were reported by measuring the temporal behaviour of the surface photo-voltage (SPV) effect, which is originated from the charge separation of the photo-excited carriers driven by the surface band bending [6,7]. In those reports, the fast SPV decay, which indicates the fast carrier recombination in the surface region, was found only on the n-type GaAs(100) surface.…”

“…2 Experimental 2.1 Ultrafast time-resolved photoemission system The schematic experimental setup of the ultrafast time-resolved photoemission system was reported in our previous paper [5,8]. The system consisted of an ultrafast laser system and a high resolution angle-resolved photoemission spectrometer.…”

Transient surface photovoltage in n- and p-GaN as probed by x-ray photoelectron spectroscopy

“…[3][4][5][6] However, except for Si ͑Refs. 7 and 8͒ and GaAs, 9,10 no transient SPV measurements using XPS have been reported to date. The high photon density of commercial monochromatic x-ray sources allows for reasonably fast ͑subsecond͒ acquisition of XPS data of a narrow spectral region to be recorded in the snap-shot mode, which can reveal the transient behavior of a sample, in a chemically addressed fashion, when subjected to external stresses like light illumination, resulting in SPV.…”

Time-Resolved Photoelectron Spectroscopies Using Synchrotron Radiation: Past, Present, and Future

“…Currently sub-ps photons are available from (i) laser, [57][58][59][60][61][62][63][64][65][66] (ii) laser-driven HHG, [67][68][69][70][71] and (iii) free electron laser. [20][21][22][23][24] Irradiating light onto a sample, electrons are pumped to unoccupied (transient) states at time < fs, followed by relaxation to the original ones.…”