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Graphene effects on photoluminescence properties of
graphene/GeSi quantum dot hybrid structures
Yulu Chen, Yinjie Ma, Dandan Chen, Wenqi Wang, Kun Ding, Qiong Wu,
Yongliang Fan, Xinju Yang, Zhenyang Zhong, Fei Xu, Zuimin Jiang*
State Key Laboratory of Surface Physics, Key Laboratory of Micro and Nano Photonic Structures
(Ministry of Education) and Department of Physics, Fudan University, Shanghai 200433, China
Introduction
Experiment
Hybrid structure of graphene on traditional semiconductors
The GeSi QDs microstructures
Carrier transferring effect
Monolayer graphene
R am an Intensity
A
Intensity(a.u)
SG
NG
4
2
0
0
1500
1600
1700
Wavelength(nm)
2000
2500
3000
G-band (~1580cm-1)
2D-band (~2676cm-1)
For 488nm:
Carrier transferring effect
NG
NG
4
1400
SG
6
SG
2
For 325nm:
surface plasmon polariton (SPP)
enhanced absorption mechanism
488nm
6
4
Mechanism
405nm
6
G-band
-1
region not covered with graphene
→ non-graphene (NG) region
Photoluminescence
325nm
6
W a v e n u m b e r(c m )
The region covered with graphene (the hybrid structure)
→ single-layer graphene (SG) region
NG
8
1500
AFM image of 10 layers GeSi quantum dots
SG
2D-band
10
(a)
4
graphene
2
(b)
0
1400
1500
1600
1400
1700
Wavelength (nm)
𝐈SG > 𝐈NG
1600
1800
2000
Wavelength (nm)
𝐈SG ≈ 𝐈NG
𝐈SG <𝐈NG
(c)
、
PL
𝐞
h
8
1.5
6
1.0
4
0.5
2
10
20
30
Temperature(K)
40
325nm
Integrated Intensity(a.u)
2.0
Theoretical calculation
12
SG
NG
Ratio
PL Intensity(a.u)
SG
NG
10
488nm


e2 E f
 2
q
   0  1   2  
8
6
4
2
15
25
35
45
E F  vF
55
Temperature(K)
1
2
2
 n, q 
a
estimation
 𝑎 = 100𝑛𝑚, 𝑛 = 1.17 × 1018
 𝑎 = 1.5 𝑛𝑚, 𝑛 = 2.17 × 1014
Supporting experiment
1.6
0.8
0.4
0.0
488nm
8
SG
NG
6
4
2
0
250 300 350 400 450 500 550
Excitation wavelength (nm)
1500
1600
1700
1800
Wavelength (nm)
PL Intensity (a.u)
325nm
100%
60 %
30 %
PL Intensity (a.u)
1.2
PL enhancement ratio at
different excitation powers
The random GeSi QDs sample
Excitation spectra
PL intensity (a.u)
Enhancement Ratio
The dependence of integrated PL intensity on the measurement temperature
SG
NG
8
6
4
2
0
1500
1600
1700
1800
Wavelength (nm)