Semiconductor Nanostructure Acoustodynamics Jens Ebbecke Linz 25/06/09.
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Transcript of Semiconductor Nanostructure Acoustodynamics Jens Ebbecke Linz 25/06/09.
GaAs
kikklikli
kkijklijklij
ESeD
EeScT
one kind of solutions: surface acoustic waves
first investigated in 1885 by Lord Rayleigh for earth quakes
surface acoustic waves
f = cSAW / p
nanostructure
Acoustoelectric Current Device (SET-SAW)
3 m
100 nm
700 nm
700 nm
RF Drive ofFrequency f
Current = e·f
Gate Voltage
Current Plateaus
f = 3.58 GHz
P = 16 dBm
T = 1.7 K
I = e f
-2.2 -2.1 -2.0 -1.9
0
1
2
3
4
5
.
Cur
rent
/ nA
Gate Voltage / V
700 nm
700 nm
-1.1
2 V
-1.2
0 V
Interaction of SAW and Impurity dot
Vga
te
RF Amplitude-30 dBm 0 dBm
PRB 68, 245310, (2003)
charging energy of a conductor: EC = e2/C Coulomb blockade
EC = e2/C >> kBT
RT >> h/2e2
zero-dimensional electronic system:
energy quantisation :
total energy:
Δ E = EN+1 - EN = Δ + EC
EF ΔE
Semiconductor quantum dots
quantized current through a static quantum dot
APL 84, 4319 (2004)
RF Amplitude
Gat
e V
olta
ge
I = 1 ef I = 1·e·f
I = 1 e f
I = 2 e f
I = 3 e f.
..
.
..
0
2
Cur
r.
/ n
A
I = e·f
Exciting: an Archimedian screw for electrons
PRB 72, 121311(R) 2005
(picture taken from Science,304, 1079 (2004)„Highlights of the recent literature“)
Growth of Carbon Nanosticks
Laser ablation of carbon leads self-organisationof carbon nanosticks->Pyroelectric effects responsible for nanostick growth-> organic nanowire son LiNbO3