ACS PRF# 50266-DNI10: Hot carrier transport in graphene Hui Zhao, University of Kansas Hot carrier diffusion in graphene Pump e e hh e h h e
eh
A tightly focused laser pulse excite carriers.
1
0
A delayed pulse probes the carriers.
μm
-2
e h
x(
τ (ps )
eh
)
2 0
he
The differential transmission of the probe pulse is measured as a function of time and space.
-4
ΔT/T 0 (10 )
2
0
Probe
t=τ
t=0
1
Epitaxial Graphene 4
D (cm2/s)
10
3
10
Reduced Graphene Oxide GaAs
2
10
1
10
The diffusion coefficient is measured and compared with other materials Si
0
100 200 Sample Temperature (K)
Energy relaxation of hot carriers
300
A pump pulse (blue) excite hot carriers A probe pulse (green) measured the time when the carriers reach the energy states probed by this pulse. Another probe pulse (red) measure the time when carrier reach the lower probing states
