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PH427 Journal Club Presentation Matt W. Graham
March 3, 2015
PH427 Journal Club Presentation Matt W. Graham
March 3, 2015
Motivation
E(k)
Te
Th
T. Mueller et al., Nature Photonics 4, 297-301
(2010).
Graphene Photodetector
Fundamental Physics• How do electrons in graphene loose their energy?
Possible applications• graphene bolometers and photosensors• designing graphene electronics
< 4 meVfv
How do electrons relax in graphene?
2
00 meV 1/100s
f
v
v
Acoustic phonons or optical phonons?
< 4 meVfv
Relationship with class materialHow do electrons relax in graphene?
200
meV 1/100s
f
v
v
Acoustic phonons or optical phonons?
200 meV
kBTe
Supercollision acoustic phonon relaxation
qac vs
qdisorder
kBTeFast
0 5 10 40 801
10
100
SC predictionTra
nsie
nt P
hot
ocu
rren
t (p
A)
Time Delay (ps)
Tl=10 K
55 K 120 K 295 K
Result From Paper: supercollison acoustic model predict how electrons relax
3 3 /ee l e
dTA T T T
dt
/
1
1B ee k Tn
e
Conclusions: a new model and physical process of how electrons relax in graphene has been developed