nano-FTIR amplitude , au |
1000 1400 Wavenumber , cm -1 |
1
5
10
15
19
Pump-Probe delay , ps
|
Carrier density , 10 18 cm -3 |
5
4
3
|
300 600 900 0 1.0 2.0
Pump-probe delay t , fs
Position , ยต m
Ultrafast carrier injection due to femtosecond near-IR photoexcitation of InAs leads to the formation of a pronounced dip ( blue line ) in the nano-FTIR spectra ( left ), whose spectral position is determined by the plasma resonance of the created hot electrons and directly relates to the carrier concentration . Changing the pump-probe delay allows for monitoring of the carrier relaxation dynamics . Such an analysis performed with IR-neaSCOPE + fs on a single InAs nanowire with 10 fs temporal & 10 nm spatial resolution reveals an ultrafast formation of a surface depletion layer and even allows for the characterization of its depth .
|