[seminar] Reminder for tommorrow: seminar @IF+online Thursday, 15.6.2023. at 11:00 - mag. phys. Ana Senkić

[Damir Dominko]

Thursday 15th June 2023 at 11:00, IF 1st wing, big lecture hall
**Microscopic investigation of intrinsic defects in transition metal 
dichalcogenide monolayers grown by chemical vapour deposition**
*mag. phys. Ana Senkić*
*Institue of Physics, Zagreb
*

Transition metal dichalcogenides (TMDs) present a broad family of 
two-dimensional (2D) materials with properties ranging from insulators 
to superconductors. With the general formula of MX_2 , the monolayer 
(1L) material consists of one plane of transition metal atoms M which is 
sandwiched between two planes of chalcogen atoms X. The most 
investigated TMD material is molybdenum disulfide – MoS_2 . This 
semiconductor has a bandgap in the visible spectrum, making it a 
promising candidate for application in photovoltaics, solar cells, 
optoelectronics, field effect transistors [1-3]. Due to its 2D nature, 
MoS_2 is extremely susceptible to the environment: humidity, 
temperature, exposure to atmosphere [4]. For these reasons, the 
synthesis of high-quality monocrystals with non-deteriorating 
properties, is of great importance. Optimum synthesis conditions yield 
high-quality crystalline structure, which then in turn, leads to great 
properties – such as optical and electronic.

In the first part of my seminar I will discuss how different synthesis 
parameters influence the morphology and optical properties of MoS_2 
samples [6]. In the second part, I will present the results of a 
detailed study on two different MoS_2 samples, synthesized under 
different growth temperatures, in order to understand the correlation 
between growth temperature and defects’ nature of the samples [6]. The 
influence of defects on optical and electronic properties is 
investigated with low-temperature photoluminescence measurements, 
room-temperature transient absorption microscopy, and Kelvin Probe Force 
Microscopy. In the final part of my talk, I will discuss how defects can 
be utilised in order to produce new properties in a host material via 
alloying and how apparently identical growth conditions can lead to 
different crystal structures.

*REFERENCES*


[1] J. S. Ross et al., Electrically tunable excitonic light-emitting 
diodes based on monolayer WSe2 p–n junctions, Nat Nanotechnol, vol. 9, 
no. 4, pp. 268–272, Apr. 2014.
[2] R. S. Sundaram et al., Electroluminescence in Single Layer MoS2, 
Nano Lett, vol. 13, no. 4, pp. 1416–1421, Apr. 2013.
[3] B. W. H. Baugher, H. O. H. Churchill, Y. Yang, and P. 
Jarillo-Herrero, Optoelectronic devices based on electrically tunable 
p–n diodes in a monolayer dichalcogenide, Nat Nanotechnol, vol. 9, no. 
4, pp. 262–267, Apr. 2014.
[4] X. Wang et al., Defect Heterogeneity in Monolayer WS2 Unveiled by 
Work Function Variance, Chemistry of Materials, vol. 31, no. 19, pp. 
7970–7978, Oct. 2019.
[5] A. Senkić, J. Bajo et al. Effects of CVD growth parameters on global 
and local optical properties of MoS2 monolayers, Materials Chemistry and 
Physics 296 (2023) 127185.
[6] A. Senkić et al. Microscopic Investigation of Intrinsic Defects in 
CVD Grown MoS2 Monolayers, IoP Nanotechnology, in review.

*LOCATION:* *Institute of Physics, 1st wing, big lecture hall + online
*


*Seminar**hosts**: Neven Šantić <mailto:nsantic at ifs.hr> and _Damir 
Dominko <mailto:ddominko at ifs.hr>

Join Zoom Meeting
https://us06web.zoom.us/j/87061512305?pwd=QjcvSWxEOWZoMmxGdGpsVVZnZUxyZz09

Meeting ID: 870 6151 2305
Passcode: 144767_*
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