Optical properties and applications
for MoS
2
-Sb
2
Te
3
-MoS
2
heterostructure materials
WENJUN LIU,
1,2,†
YA-NAN ZHU,
3,†
MENGLI LIU,
1
BO WEN,
3
SHAOBO FANG,
2
HAO TENG,
2
MING LEI,
1,5
LI-MIN LIU,
3,4,6
AND ZHIYI WEI
2,
*
1
State Key Laboratory of Information Photonics and Optical Communications, School of Science, Beijing University of Posts and
Telecommunications, Beijing 100876, China
2
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
3
Beijing Computational Science Research Center, Beijing 100193, China
4
School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100083, China
5
e-mail: mlei@bupt.edu.cn
6
e-mail: limin.liu@csrc.ac.cn
*Corresponding author: zywei@iphy.ac.cn
Received 20 November 2017; revised 16 January 2018; accepted 18 January 2018; posted 23 January 2018 (Doc. ID 313957);
published 28 February 2018
Two-dimensional (2D) materials with potential applications in photonic and optoelectronic devices have at-
tracted increasing attention due to their unique structures and captivating properties. However, generation
of stable high-energy ultrashort pulses requi res further boosting of these materials’ optical properties, such
as higher damage threshold and larger modulation depth. Here we investigate a new type of heterostructure
material with uniformity by employing the magn etron sputtering technique. Heterostructure materials are syn-
thesized with van der Waals heterostructures consisting of MoS
2
and Sb
2
Te
3
. The bandgap, carrier mobility, and
carrier concentration of the MoS
2
-Sb
2
Te
3
-MoS
2
heterostructure materials are calculated theoretically. By using
these materials as saturable absorbers (SAs), applications in fiber lasers with Q-switching and mode-locking states
are demonstrated experimentally. The modulation depth and damage threshold of SAs are measured to be 64.17%
and 14.13 J∕cm
2
, respectively. Both theoretical and experimental results indicate that MoS
2
-Sb
2
Te
3
-MoS
2
het-
erostructure materials have large modulation depth, and can resist high power during the generation of ultrashort
pulses. The MoS
2
-Sb
2
Te
3
-MoS
2
heterostructure materials have the advantages of low cost, high reliability, and
suitability for mass production, and provide a promising solution for the developmen t of 2D-material-based
devices with desirable electronic and optoelectronic properties.
© 2018 Chinese Laser Press
OCIS codes: (160.4330) Nonlinear optical materials; (140.4050) Mode-locked lasers; (140.3510) Lasers, fiber.
https://doi.org/10.1364/PRJ.6.000220
1. INTRODUCTION
Two-dimensional (2D) materials have exhibited great promise
in microelectronics and optoelectronics since the discovery of
graphene [1–9]. They possess special physical features, and can
be used in the construction of various functional devices.
Considered as one of the keys to modern technology, low-
dimensional materials have been consistently reported and
deeply investigated [10–20]. For example, carbon nanotubes
(CNTs) and some 2D materials have been applied to the prepa-
ration of saturable absorption devices, photodetectors, and
optical modulators [21–28].
As a saturable absorption material, CNTs are not sensitive to
polarization, and have relatively high damage threshold and
environmental stability. However, their scattering loss needs
to be further reduced [29–31]. Graphene, which is cheap
and convenient to prepare, also has a high damage threshold
and ultra-fast recover y time [2–4]. As a special zero-gap semi-
conductor, graphene nearly absorbs the light for each band,
which makes it suitable as an ultra-wide-band saturable
absorber (SA). However, the modulation depth and non-
saturable loss should be optimized [32–35]. Topological insula-
tors (TIs), the generic term for materials with topological
electronic properties, have the advantages of excellent saturable
absorption property, large optical modulation depth, and high
third-order nonlinear refractive index. Their narrow bandgap
enhances their ability to absorb the broadband spectrum,
which has potential applications in ultrafast optics [36–38].
Nevertheless, their thermal damage threshold should be im-
proved [36–38]. Transition metal dichalcogenides (TMDs)
have been widely investigated in nonlinear optics after graphene
[39–45]. To date, molybdenum disulfide (MoS
2
), tungsten
220
Vol. 6, No. 3 / March 2018 / Photonics Research
Research Article
2327-9125/18/030220-08 Journal © 2018 Chinese Laser Press