MoS2 van der Waals Heterostructure Photodiodes

Subscriber access provided by Kaohsiung Medical University

Letter

Atomic Layer GaSe/MoS2 van der Waals Heterostructure Photodiode with Low Noise and Large Dynamic Range Arnob Islam, Jaesung Lee, and Philip X.-L. Feng ACS Photonics, Just Accepted Manuscript • DOI: 10.1021/acsphotonics.8b00318 • Publication Date (Web): 10 Jun 2018 Downloaded from http://pubs.acs.org on June 11, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Photonics

Atomic Layer GaSe/MoS2 van der Waals Heterostructure Photodiodes with Low Noise and Large Dynamic Range Arnob Islam, Jaesung Lee and Philip X.-L. Feng* Department of Electrical Engineering & Computer Science, Case School of Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA Abstract We report on the demonstration of atomic layer van der Waals (vdW) heterostructure photodiodes operating in the visible regime, enabled by stacking single- to few-layer n-type molybdenum disulfide (MoS2) on top of few-layer p-type gallium selenide (GaSe) crystals. The atomic layer vdW photodiode exhibits excellent photoresponsivity of ~3A/W at the wavelength of 532 nm when symmetric few-layer graphene (FLG) contacts with low contact resistance are used.

On the other hand, for GaSe/MoS2 photodiode with

asymmetric GaSe/FLG and MoS2/gold (Au) contacts, very low noise equivalent power of NEP ~10-14 W/√ is obtained due to dark current reduction, which demonstrates the feasibility of detecting sub-pW ( 102

10-1

Psat = 2µW

0

Device 1 0 1 Bias,VD(V)

10

10

100

Iph (nA)

D

10-2

1

VD = 2V

275

FB

RB

0.1

Incident Power,P (µW)

Current, I (nA)

10

1

0.1

b

-1

VD = -2V VD = 2V

Responsivity, R (mA/W)

hν

hν

a

Responsivity, R (mA/W)

almost the same extent, which results in exhibiting anti-ambipolar behavior (Figure 3l)26.

Current, I (µA)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 22

-1

0 Bias,V (V) D

1

2

20

0

f

Psat = 1µW 10 1 0.1 0.01

0

2 4

6

8 10

0 2 4 6 8 10 Incident Power,P (µW)

Figure 4. Photoresponse characteristics measured from the vdW photodiodes. (a) Photoresponse obtained from device #1 (VG = 0V) under FB (light blue shaded region) and RB (red shaded region) conditions along with corresponding band diagrams pertaining to the device physics behind the photoresponse. (b) and (c) ℜ values for different optical illumination at 532 nm wavelength and photocurrent trend upon increasing optical illumination respectively for device #1. (d) – (f) The same plots for device #2 (VG = -9V). Insets in (c) and (f) show photocurrent under increasing illumination in logarithmic scale.

Now we investigate the photoresponse of these devices. A 532nm diode laser has been used to measure the photocurrent generated from this vdW heterostructure photodiode, as 532nm laser can be absorbed by both MoS2 (Ref. 8), and GaSe (Ref. 27). During illumination, we place the laser spot on the active area of the photodetector which is shown in Figure 1c and 1d. For device #1, we obtain higher responsivity ( ℜ =

I ph P

) ~200-300 mA/W at low incident power (~nW level)

as a result of higher absorption in this device, which consists of thicker flakes (multi-layer GaSe

-10-

ACS Paragon Plus Environment

Page 11 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Photonics

and tri-layer MoS2). As we use thinner GaSe and MoS2 flakes in device #2, we obtain lower ℜ ~ 50 mA/W from device #2. Figure 4b and 4e show the optical power dependent ℜ for device #1 and #2 respectively with decreasing ℜ at higher P, which might be related to photogating effect during lateral transport of photogenerated carriers.

Ideally, in a conventional silicon (Si)

photodiode, during the operation of the photodetector, the diode is biased at RB, where ℜ is higher and the dark current is low. However, for vdW heterojunction diode, it is not always true as it also strongly depends on the metal-semiconductor contacts. Photocurrent can be generated at both forward and reverse bias conditions, even ℜ can be higher in forward bias of the photodiode unlike in conventional photodiodes12. It can be explained by the corresponding band diagrams in Figure 4a and 4b. At FB, under illumination, the photogenerated majority carriers spatially confined in each layer of GaSe and MoS2 can go through recombination by inelastic tunneling or transport by thermionic emission at p-n junction potential barrier, which contributes to the photocurrent4.

In this study, we observe almost one order of magnitude higher

photocurrent at FB for device #2. This is because at RB, photogenerated electrons and holes are partially blocked at the Schottky barriers located at both ends (Figure 4d). On the other hand, for device #1, for both FB and RB, photocurrents are similar due to better metal-semiconductor contacts at both ends (Figure 4a).

These results indicate the role of metal-semiconductor

contacts on measured photoresponse. For device #2, we observe large photocurrent (Iph) to dark current (Idark) contrast ratio, Iph/Idark> 102 owing to very low Idark (~10-20pA) at both forward and reverse bias (Figure 4d), whereas for device #1 we observe quite low Iph/Idark at zero gate voltage (VG) (Figure 4a). Moreover, gate voltage (VG) tuning can also play a role to maximize Iph/Idark (see Supporting

-11-


ACS Photonics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 22

Information, S2). Larger Iph/Idark improves the dynamic range (DR) of the photodetector. We can calculate DR by using the following formula28:

æP ö DR = 10log çç sat ÷ , ÷ çè NEP ÷ ø

(1)

where, Psat is the optical power at which photocurrent starts to deviate from linear characteristics and saturate upon increasing optical illumination, and NEP is noise-equivalent-power. NEP can be expressed as5: NEP =

in , Â

(2)

1

where, in = (2eBI dark ) 2 is shot noise which is a fundamental noise source for the measurable Idark. Figure 4c and 4f show the Iph versus P for device #1 and #2, from which we are able to know Psat and calculate DR using Eq. 1. We obtain DR of ~70dB for device #2, which is significantly better than values reported in the literature for 2D photodetectors28,29. We obtain very low NEP for device #2 under forward bias. At 2V bias, we achieve NEP = 10-14 W/√Hz (Figure 5a). It dictates that in principle, we will be able to detect sub-pW level optical illumination using this photodiode. We also calculate normalized photocurrent to dark current ratio (NPDR), which is defined as:30

NPDR ≡

Iph Idark

P

=

1 2q . NEP Idark

(3)

We obtain NPDR value of on the order of 108 mW-1 for nW level optical illumination. Thus, this photodiode provides an ideal platform for detecting ultralow level illumination. We compute the detectivity of the photodiodes by using the following equation6 12

D* =ℜ×( AB) / in , -12-


(4)

Page 13 of 22

where A is the effective area of the photodetector, B is bandwidth. The unit of detectivity is Jones (cmHz1/2/W). For device #2, the active area (A) of the device is ~ 100 µm2. By operating device #2 in forward bias, we achieve the highest D* for the photodiode, which is on the order of 1010 Jones (Figure 5b). Furthermore, we also characterize the dynamic photoresponse of device #2. We find that rise time ( t r ) of the device is ~50ms (Figure 5c-d). The response time of the device is not fast as we expect from a photodiode, owing to the fact that device #2 is not exactly a vertical vdW heterostructure. Carriers are still trapped during the lateral transport from the heterojunction to the metal contacts. Response time can be improved by making truly vertical vdW heterostructure with only out-of-plane photogenerated carriers extraction considering faster

10-11 D*(Jones)

NEP (W/Hz-1/2)

carrier transit time.

10-12 10-13

1010 109 108

-14

10

a

-2

-1 0 Bias (V) Laser ON

1

2

0.08

0.04

c

0

-2

-1 0 Bias (V)

1

2

Laser OFF

0.12

0.00

b

Photocurrent (a.u.)

Photocurrent (a.u.)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Photonics

0.12

0.08

0.04

τr =~50ms 0.00

200 400 600 800 1000 Time (ms)

d

200 240 280 320 360 400 Time (ms)

Figure 5. Noise characteristics and dynamic response of the GaSe/MoS2 photodiode. (a) and (b) NEP and D* values obtained at the FB and RB condition of device #2 (VG = -9V, P=5nW). (c) and (d) Dynamic photoresponse obtained from device #2 (VG = 3V, VD = 2V, P=3nW).

-13-


ACS Photonics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 22

In order to observe the photocurrent contribution from the different locations of the photodiode, e.g., bare MoS2 or GaSe, MoS2/GaSe, MoS2/Gr or GaSe/Gr etc., we perform photocurrent mapping with 532nm laser (~1µm spot size) on device #3. From the mapping results (Figure 6a), we have found that the maximum photocurrent contribution originates from the MoS2/GaSe heterostructure region. In literature, on SiO2/Si substrate, GaSe and MoS2 have peak responsivities around 3.3eV and ~2.2eV respectively 31, 32 . Therefore, using 532nm (~2.3eV) laser, although we obtain lower absorption in GaSe, higher absorption in MoS2 occurs.

In ideal case, for GaSe/MoS2

heterostructures, peak responsivity wavelength will be determined by peak responsivity of the material that has larger number of layers. On the other hand, MoS2 has direct bandgap in its single-layer form, which can absorb more than few-layer GaSe (indirect bandgap) does, although it is thinner compared to GaSe. On top of that, multi-layer interference at MoS2/GaSe/SiO2/Si can also play an important role in absorption, thus photocurrent, which will make the situation more complex. Therefore, in reality, peak responsivity of heterostructure will be determined by the interplay of all these effects. In order to investigate this, we use 405nm laser (3.07eV) to conduct photocurrent measurement and compare the photoresponse with 532nm laser illumination for device #3 (1L MoS2 and 5-6L GaSe). We have found that using 405nm laser illumination, we obtain 2-3 times higher responsivity at different incident power levels (Figure 6b). It is also worth mentioning that, for device #3, responsivity (~3A/W) is significantly higher than previous devices, although its comparatively high Idark limits its DR (63dB) and NEP (~1013

W/√Hz). Detailed photoresponse of this device is presented in Supporting Information, S3.

-14-


Page 15 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Photonics

Figure 6. Photocurrent mapping and wavelength dependent photoresponse. (a) Photocurrent mapping on device #3 with 532nm laser (VD =1.8V, VG=-10V, P =100nW). (b) Comparison of responsivity for device #3 under 532nm and 405nm laser illumination (VD =2V, VG=-10V), where red circle indicates the position of laser spot.

In Table 1, we compare the performance of our photodiodes with other atomically thin photodiodes (homojunction and heterojunction) reported. For fair comparison, we only focus on the heterostructures where at least one of the constituting materials is atomically thin (i.e., 1layer to 3-layer). We find that in terms of ℜ , our device has similar or better performance compared to that of existing vdW heterostructures. In other important aspects such as NEP, DR and response time, this study has yielded excellent performance in metrics that have not been attained in previous studies. Recently there has been a study of GaSe/MoS2 heterostructure photodetector35, which shows responsivity of ~60mA/W and response time of ~80ms, comparable to those of device #2 in this work. However, linear dynamic range of that device should be lower than device #2 due to smaller Iph/Idark ratio35.

-15-


ACS Photonics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 16 of 22

Table 1: Comparison of device performance with other atomically thin photodiodes in literature. van der Waals Heterostructures

Thickness

ℜ (mA/W)

NEP (W/√)

DR (dB)

Response Time (ms)

Ref.

p-MoS2/n-WSe2

1L/1L

11 (@532 nm)

N.A.

N.A.

N.A.

9

p-Black Phosphorus/n-MoS2

11 nm/1L

420 (@633 nm)

N.A.

N.A.

N.A.

12

p-WSe2/n-WSe2

1L

210 (@532 nm)

N.A.

N.A.

N.A.

33

p-GaSe/n-MoSe2

1L/1L

30 (White light)

N.A.

N.A.

N.A.

34

p-GaSe/n-MoS2 (CVD)

3L/1L

~60 (@300nm)

N.A.

N.A.

80

35

3L/1L

~50 (@532 nm)

~10-14

70

50

5-6L/1L

~3000 (@532nm)

~10-13

63

N. A.

~15 to 20L/3L

~350 (@532 nm)

~10-12

54

N. A.

p-GaSe/n-MoS2

This work

Conclusion In summary, we have demonstrated GaSe/MoS2 vdW heterostructure photodiodes and extensively analyzed their performance metrics, and evaluated their figures-of-merit as photodetectors. We have attained vdW heterojunction photodiodes with ultralow noise (10-14 W/Hz1/2) and large dynamic range (DR~70dB) for GaSe/MoS2 vdW heterostructures with asymmetric contacts. In addition, these atomic layer vdW photodiodes can also exhibit excellent responsivity (~3A/W) by using FLG contacts with low contact resistance. The results also show that metal-semiconductor junctions can play a crucial role in suppressing dark current and regulating the photoresponse in order to realize high-performance vdW photodiodes. We believe -16-


Page 17 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Photonics

that this study can serve as a great guideline for designing vdW photodiodes by taking into account the important trade-off between high responsivity and low noise or high DR, imposed by the choice of metal-semiconductor contacts. This study opens new opportunities for employing p-n materials pairs from both TMDCs and group III mono-chalcogenides, to create 2D nanoelectronics, optoelectronic devices, and such devices on flexible substrates.

-17-


ACS Photonics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Methods We fabricate vdW heterostructures by using completely dry, wet-chemical-free transfer techniques. In this process, we exfoliate GaSe and MoS2 flakes from their bulk crystals onto polydimethylsiloxane (PDMS) stamps and choose candidate flakes under an optical microscope. After that, we stack the chosen flakes on pre-patterned substrates with electrodes (Au) together, to form vdW heterostructures by using proper alignment with micro-manipulators in a transfer stage under an optical microscope. After fabricating the devices, we thermally anneal them at 250˚C for 1 hour under constant N2 flow in moderate vacuum (~20 mTorr)36. For Raman and photoluminescence (PL) measurements, a 532nm diode laser is focused on the sample using a 50× microscope objective and scattered light (for Raman) and photoluminescence from the sample is collected in backscattering geometry, and is then guided to a spectrometer (Horiba iHR550). Grating settings of 2400g mm−1 and 1200g mm-1 are used for Raman and PL respectively. The signals are recorded using a liquid-nitrogen-cooled CCD. Spot size of the laser is optimized to be~1µm. Laser power on the sample is kept to be ~200µW during Raman and PL measurements. For low noise electrical measurements of the fabricated vdW diodes, a Kethley-4200 SCS semiconductor parameter analyzer is employed (Figure 2). A 532 nm diode laser with ~1 µm spot size is used for optical illumination. For photocurrent measurements, we use a low noise current pre-amplifier (SR570) with a data acquisition card (DAQ) card, which is controlled by a custom-made LabView program. For dynamic photoresponse measurement, we use a chopper to modulate the laser and record the photoresponse by using an oscilloscope. All photocurrent measurements are performed in moderate vacuum (10-20 mTorr) and at room temperature.

-18-


Page 18 of 22

Page 19 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Photonics

Acknowledgments: We acknowledge the support from National Science Foundation CAREER Award (ECCS #1454570).

Part of the device fabrication was performed at the Cornell

Nanoscale Science and Technology Facility (CNF), a member of the National Nanotechnology Infrastructure

Network

(NNIN),

supported

by

the

National

Science

Foundation

(ECCS#0335765).

Supporting Information Available: This material is available free of charge via the Internet at http://pubs.acs.org.

Estimation of thickness of GaSe and MoS2 flake by using Raman

spectroscopy and gate tuning of the Photodiode.

-19-


ACS Photonics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

References 1. Novoselov, K. S.; Mishchenko, A.; Carvalho, A.; Neto, A. H. C. 2D materials and van der Waals heterostructures. Science 2016, 353, 6298. 2. Geim, A. K.; Grigorieva, I. V. Van der Waals heterostructures. Nature 2013, 499, 419–425. 3. Wang, X.; Xia, F. Van der Waals heterostructures: Stacked 2D materials shed light. Nat. Mater. 2015, 14, 264– 265. 4 . Xia, W.; Dai, L.; Yu, P.; Tong, X.; Song, W.; Zhang, G.; Wang, Z. Recent progress in van der Waals heterojunctions. Nanoscale 2017, 9, 4324–4365. 5. Britnell, L.; Ribeiro R. M.; Eckmann A.; Jalil R.; Belle B. D.; Mishchenko A.; Kim Y. J.; Gorbachev R. V.; Georgiou T.; Morozov S. V.; Grigorenko A. N.. Strong light-matter interactions in heterostructures of atomically thin films. Science. 2013, 340, 1311-1314. 6. Buscema, M.; Island, J. O.; Groenendijk, D. J.; Blanter, S. I.; Steele, G. A.; van der Zant, H. S. J.; CastellanosGomez, A. Photocurrent generation with two-dimensional van der Waals semiconductors. Chem. Soc. Rev. 2015, 44, 3691–3718. 7. Fazio, D. D.; Goykhman, I.; Yoon, D.; Bruna, M.; Eiden, A.; Milana, S.; Sassi, U.; Barbone, M.; Dumcenco, D.; Marinov, K.; Kis, A.; Ferrari, A. C. High Responsivity, Large-Area Graphene/MoS2 Flexible Photodetectors. ACS Nano 2016, 10, 8252–8262. 8. Tsai, D.S.; Liu, K.K.; Lien, D.H.; Tsai, M.L.; Kang, C.F.; Lin, C.A.; Li, L.J.; He, J.H., Few-layer MoS2 with high broadband photogain and fast optical switching for use in harsh environments. ACS Nano 2013, 7, 3905-3911. 9. Lee, C.-H.; Lee, G.-H.; Zande, A. M. V. D.; Chen, W.; Li, Y.; Han, M.; Cui, X.; Arefe, G.; Nuckolls, C.; Heinz, T. F.; Guo, J.; Hone, J.; Kim, P. Atomically thin p–n junctions with van der Waals heterointerfaces. Nat. Nanotechnol. 2014, 9, 676–681. 10. Hong, X.; Kim, J.; Shi, S.-F.; Zhang, Y.; Jin, C.; Sun, Y.; Tongay, S.; Wu, J.; Zhang, Y.; Wang, F. Ultrafast charge transfer in atomically thin MoS2/WS2 heterostructures. Nat. Nanotechnol. 2014, 9, 682–686. 11. Zhang, K.; Zhang, T.; Cheng, G.; Li, T.; Wang, S.; Wei, W.; Zhou, X.; Yu, W.; Sun, Y.; Wang, P.; Zhang, D.; Zeng, C.; Wang, X.; Hu, W.; Fan, H. J.; Shen, G.; Chen, X.; Duan, X.; Chang, K.; Dai, N. Interlayer Transition and Infrared Photodetection in Atomically Thin Type-II MoTe2/MoS2 van der Waals Heterostructures. ACS Nano 2016, 10, 3852–3858. 12. Deng, Y.; Luo, Z.; Conrad, N. J.; Liu, H.; Gong, Y.; Najmaei, S.; Ajayan, P. M.; Lou, J.; Xu, X.; Ye, P. D. Black Phosphorus–Monolayer MoS2 van der Waals Heterojunction p–n Diode. ACS Nano 2014, 8, 8292–8299. 13. Ganatra, R.; Zhang, Q. 2014. Few-layer MoS2: a promising layered semiconductor. ACS Nano, 2014, 8, 40744099. 14. Wang, F.; Wang, Z.; Xu, K.; Wang, F.; Wang, Q.; Huang, Y.; Yin, L.; He, J. Tunable GaTe-MoS2 van der Waals p–n Junctions with Novel Optoelectronic Performance. Nano Lett. 2015, 15, 7558–7566. 15. Zhou, X.; Cheng, J.; Zhou, Y.; Cao, T.; Hong, H.; Liao, Z.; Wu, S.; Peng, H.; Liu, K.; Yu, D. Strong SecondHarmonic Generation in Atomic Layered GaSe. J. Am. Chem. Soc. 2015, 137, 7994–7997. 16. Late, D. J.; Liu, B.; Luo, J.; Yan, A.; Matte, H. S. S. R.; Grayson, M.; Rao, C. N. R.; Dravid, V. P. GaS and GaSe Ultrathin Layer Transistors. Adv. Mater. 2012, 24, 3549–3554. 17. Hu, P.; Wen, Z.; Wang, L.; Tan, P.; Xiao, K. Synthesis of Few-Layer GaSe Nanosheets for High Performance Photodetectors. ACS Nano 2012, 6, 5988–5994. 18 . Kang, J.; Tongay, S.; Zhou, J.; Li, J.; Wu, J. Band offsets and heterostructures of two-Dimensional semiconductors. Appl. Phys. Lett. 2013, 102, 012111. 19. Aziza, Z. B.; Henck, H.; Pierucci, D.; Silly, M. G.; Lhuillier, E.; Patriarche, G.; Sirotti, F.; Eddrief, M.; Ouerghi, A. Van der Waals Epitaxy of GaSe/Graphene Heterostructure: Electronic and Interfacial Properties. ACS Nano 2016, 10, 9679–9686. -20-


Page 20 of 22

Page 21 of 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Photonics

20. Yuan, X.; Tang, L.; Liu, S.; Wang, P.; Chen, Z.; Zhang, C.; Liu, Y.; Wang, W.; Zou, Y.; Liu, C.; Guo, N.; Zou, J.; Zhou, P.; Hu, W.; Xiu, F. Arrayed van der Waals Vertical Heterostructures Based on 2D GaSe Grown by Molecular Beam Epitaxy. Nano Lett. 2015, 15, 3571–3577. 21. Du, Y.; Yang, L.; Zhang, J.; Liu, H.; Majumdar, K.; Kirsch, P. D.; Ye, P. D. MoS2 Field-Effect Transistors with Graphene/Metal Heterocontacts. IEEE Electron Device Lett. 2014, 35, 599–601. 22. Wang, T.; Li, J.; Zhao, Q.; Yin, Z.; Zhang, Y.; Chen, B., Xie, Y.; Jie, W. High-Quality GaSe Single Crystal Grown by the Bridgman Method. Materials 2018, 11, 186. 23. Zhang, D.; Jia, T.; Dong, R.; Chen, D. Temperature-Dependent Photoluminescence Emission from Unstrained and Strained GaSe Nanosheets. Materials 2017, 10, 1282. 24. Li, X.; Lin, M.-W.; Puretzky, A. A.; Idrobo, J. C.; Ma, C.; Chi, M.; Yoon, M.; Rouleau, C. M.; Kravchenko, I. I.; Geohegan, D. B.; Xiao, K. Controlled Vapor Phase Growth of Single Crystalline, Two-Dimensional GaSe Crystals with High Photoresponse. Sci. Rep. 2014, 4. 25 . Nourbakhsh, A.; Zubair, A.; Dresselhaus, M. S.; Palacios, T. Transport Properties of a MoS2/WSe2 Heterojunction Transistor and Its Potential for Application. Nano Lett. 2016, 16 (2), 1359–1366. 26. Jariwala, D.; Howell, S.L.; Chen, K.S.; Kang, J.; Sangwan, V.K.; Filippone, S.A.; Turrisi, R.; Marks, T.J.; Lauhon, L.J.; Hersam, M.C. Hybrid, gate-tunable, van der Waals p–n heterojunctions from pentacene and MoS2. Nano letters 2015, 16, 497-503 27. Abderrahmane, A.; Jung, P.G.; Kim, N.H.; Ko, P.J.; Sandhu, A. Gate-tunable optoelectronic properties of a nano-layered GaSe photodetector. Optical Materials Express 2017, 7, 587-592. 28. Sanctis, A. D.; Jones, G. F.; Wehenkel, D. J.; Bezares, F.; Koppens, F. H. L.; Craciun, M. F.; Russo, S. Extraordinary linear dynamic range in laser-Defined functionalized graphene photodetectors. Sci. Adv. 2017, 3. 29. Chowdhury, R. K.; Maiti, R.; Ghorai, A.; Midya, A.; Ray, S. K. Novel silicon compatible p-WS2 2D/3D heterojunction devices exhibiting broadband photoresponse and superior detectivity. Nanoscale 2016, 8, 13429– 13436. 30. Islam, A.; Feng, P. X.-L. Effects of asymmetric Schottky contacts on photoresponse in tungsten diselenide (WSe2) phototransistor. J. Appl. Phys. 2017, 122, 085704. 31. Lei, S.; Ge, L.; Liu, Z.; Najmaei, S.; Shi, G.; You, G.; Lou, J.; Vajtai, R.; Ajayan, P.M.; Synthesis and photoresponse of large GaSe atomic layers. Nano Lett. 2013, 13, 2777-2781. 32. Dhyani, V.; Das, S. High-Speed Scalable Silicon-MoS2 PN Heterojunction Photodetectors. Sci. Rep. 2017, 7, 44243. 33 . Baugher, B. W. H.; Churchill, H. O. H.; Yang, Y.; Jarillo-Herrero, P. Optoelectronic devices based on electrically tunable p–n diodes in a monolayer dichalcogenide. Nat. Nanotechnol. 2014, 9, 262–267. 34. Li, X.; Lin, M.-W.; Lin, J.; Huang, B.; Puretzky, A. A.; Ma, C.; Wang, K.; Zhou, W.; Pantelides, S. T.; Chi, M.; Kravchenko, I.; Fowlkes, J.; Rouleau, C. M.; Geohegan, D. B.; Xiao, K. Two-Dimensional GaSe/MoSe2 misfit bilayer heterojunctions by van der Waals epitaxy. Sci. Adv. 2016, 2. 35. Zhou, N.; Wang, R.; Zhou, X.; Song, H.; Xiong, X.; Ding, Y.; Lü, J.; Gan, L.; Zhai, T. P‐GaSe/N‐MoS2 Vertical Heterostructures Synthesized by van der Waals Epitaxy for Photoresponse Modulation. Small 2018, 14, 1702731. 36. Yang, R.; Zheng, X.; Wang, Z.; Miller, C. J.; Feng, P. X.-L. Multilayer MoS2 transistors enabled by a facile dryTransfer technique and thermal annealing. J. Vac. Sci. & Technol. B. 2014, 32, 061203.

-21-


ACS Photonics 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Table of Content (TOC) graphic 80x39mm (300 x 300 DPI)


Page 22 of 22

MoS2 van der Waals Heterostructure Photodiodes

Recommend Documents