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Identifier |
000403270 |
Title |
Study of visible and infrared sensors based on two dimensional materials |
Alternative Title |
Μελέτη αισθητήρων ορατής και υπέρυθρης ακτινοβολίας βασισμένους σε διδιάστατα υλικά |
Author
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Σταυρακάκη, Αλεξάνδρα Γ.
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Thesis advisor
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Γεωργακίλας, Αλέξανδρος
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Reviewer
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Χατζόπουλος, Ζαχαρίας
Σαββίδης, Παύλος
Δεληγεώργης, Γεώργιος
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Abstract |
Detection of light (photodetection) is the prominent issue which has been widely investigated the recent decades by the research community in optoelectronics and used for applications in biomedical imaging, molecular sensing and telecommunication.
Transition metal dichalcogenides (TMDs) belong to the family of 2 dimensional (2D) materials. They exhibit great optical properties and have attracted the interest of optoelectronic research.
The scope of this thesis is to construct and investigate photodetecting devices based on MoS2, a member of the 2D – TMDs group. MoS2 was used through a dispersion (liquid phase exfoliated MoS2) in order to fabricate a significant amount of devices for testing. Raman analysis was used for the characterization of the deposited MoS2 films. From Raman spectra a trilayer form of MoS2 crystal was estimated. The photodetectors that were tested were fabricated with different metal electrodes and deposited on different substrates.
Concerning the first samples, MoS2 was deposited on Si/SiO2 substrate with asymmetric Pt/Ti metal contacts. Electrical measurements were carried out for testing the operation of the devises without illumination (dark current measurements) revealing non – linear and symmetric I – V characteristics. The devices were also tested under illumination (photocurrent measurements) using a laser beam of wavelength ι = 405nm, where a non – linear photoresponse was measured as a function to incident laser power.
The second series of samples contains MoS2 on glass substrate with symmetric Au metal electrodes. According the respective I – V characteristics (dark current) an ohmic – like behavior was observed. Under illumination a linear dependence of photocurrent to incident power was measured. From power dependence measurements responsivity at the order of nA/W was calculated and quantum efficiency was also extracted from the power of light incident to the area of the material (MoS2).
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Language |
English |
Subject |
MoS2 |
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Photocurrent |
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Photodetectors |
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Responsivity |
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Αισθητήρες |
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Απόκριση |
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Δισουλφίδιο του Μολυβδαινίου |
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Φωτόρευμα |
Issue date |
2016-11-18 |
Collection
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School/Department--School of Sciences and Engineering--Department of Physics--Post-graduate theses
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Type of Work--Post-graduate theses
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Views |
468 |