Regensburg 2019 – wissenschaftliches Programm
O 64.9: Poster
Mittwoch, 3. April 2019, 17:45–20:00, Poster B1
Ultrafast time-resolved photoemission electron microscopy of indium arsenide nanowires with variable crystal phase — •Lukas Wittenbecher1, 2, Jan Vogelsang1, Sebastian Lehmann1, Kimberly Dick Thelander1, Donatas Zigmantas2, and Anders Mikkelsen1 — 1Department of Physics, Lund University, Sweden — 2Chemical Physics, Lund University, Sweden
The III-V nanowire (NW) technology platform has reached a level of advancement that allows atomic scale control as well as flexible device integration. In particular, controlled axial stacking of segments with Wurtzite (Wz) and Zinc blende (Zb) crystal phase is uniquely possible in the NWs. We have previously found that multiphoton electron excitations from indium arsenide (InAs) NWs with Wz and Zb segments can controllably varied across the crystal segments that also retain their electronic properties to the smallest possible scales. However, the effect of the crystal phase on the ultrafast dynamical behavior of photo-excited electrons in these NWs has so far not been explored.
In the present study we combine photoemission electron microscopy with ultrafast optical pump-probe techniques to investigate the photo-excitation dynamics in InAs NWs with alternating Wz and Zb segments with 50 nm spatial and 20 fs temporal resolution. We focus on the initial stages of the electron relaxation process, and we interpret the observed signals as signatures of the thermalization and cooling of photo-excited electrons. We find small differences in the observed dynamics between Wz and Zb segments phase depending on the excitation conditions.