Μελέτη της απόκρισης φωτοανιχνευτών ΖnO σε μικροδομημένο και επίπεδο υπόστρωμα Si (ZnO/Si)

Χατζηγιαννάκης, Γεώργιος; Chatzigiannakis, Georgios

dc.contributor.author	Χατζηγιαννάκης, Γεώργιος	el
dc.contributor.author	Chatzigiannakis, Georgios	en
dc.date.accessioned	2019-07-23T07:32:35Z
dc.date.available	2019-07-23T07:32:35Z
dc.date.issued	2019-07-23
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/49119
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.9325
dc.description	Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Επιστήμη και Τεχνολογία Υλικών”	el
dc.rights	Αναφορά Δημιουργού - Παρόμοια Διανομή 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-sa/3.0/gr/	*
dc.subject	Ετεροεπαφές	el
dc.subject	Φωτοανιχνευτές	el
dc.subject	Μικροδομημένο πυρίτιο	el
dc.subject	Οξείδιο του ψευδαργύρου	el
dc.subject	Heterojunctions	en
dc.subject	Photodetectors	en
dc.subject	Zinc oxide	en
dc.subject	Microstructured silicon	en
dc.subject	Ημιαγωγοί	el
dc.subject	Semiconductors	en
dc.title	Μελέτη της απόκρισης φωτοανιχνευτών ΖnO σε μικροδομημένο και επίπεδο υπόστρωμα Si (ZnO/Si)	el
dc.title	Responsivity of photodetectors ZnO on laser-mictrostructured and planar Si (ZnO/Si)	en
heal.type	masterThesis
heal.classification	Οπτοηλεκτρονική	el
heal.classification	Optoelectronics	el
heal.language	el
heal.access	free
heal.recordProvider	ntua	el
heal.publicationDate	2019-07-04
heal.abstract	ZnO is semiconductor a very useful semiconductor in optoelectronics, especially for the detection of UV-irradiation due to its wide and direct bandgap (3.3eV), large large exciton binding energy (60 meV) and high transparency (>80%) in the visible wavelength region. On the other hand, Si with an indirect bandgap of 1.07 eV, is extremely used as a visible-light detector. Thus, ZnO/Si heterojunctions could be used as photodetectors of UV and visible wavelengths. Microstructruring of silicon using nanosecond laser pulses seems to be a very promising procedure for the development of photodiodes (ZnO/Si) with enhanced spectral responsivity due to the increased specific area and light absorption including IR-irradiation because of microstructured silicon. In the present study, four ZnO/Si heterojunctions were fabricated on microstructured and flat substrates Si of both p-type and n-type. Initially, Si substrates were irradiated with nanosecond lasers in a sulfur hexafluoride (SF6) environment, resulting in a network of conical microspikes on its surface. Coating of the microstructured and flat silicon substrates with thin-film of ZnO was performed by the Atomic Layer Deposition method (ALD). Subsequently, metallic contacts on both sides of the devices were constructed by thermal evaporation method in order to study their electrical characteristics. For the calculation of the response of the two photodiodes at different wavelengths, photoconductivity measurements were made using a Xenon lamp and a monochromator. Οptical measurements for diffused and specular reflectivity were perfomed in order to calculate the absorptance of the heterojunctions.The morphology and the chemical composition of heterojunctions surface were studied by scanning electron microscopy (SEM) and X-ray emission spectroscopy (EDS), while the detection of various chemical elements in depth with respect to the surface was performed using secondary ions mass spectroscopy (SIMS). From the above-mentioned electrical and optical measurements, there is a rectifying behavior for the two devices (ZnO/p-Si), with a much higher responsivity 8 for the microstructured photodiode at all wavelengths, which is related to the increase of the active surface area and the reduced reflectivity.On the contrary, the behavior of the device on n-Si substrate was quite different with the flat device exhibiting selective responsivity depending on the radiation wavelength and the polarization conditions, while the microstructured device showed generally reduced light detection.	en
heal.abstract	Στην παρούσα εργασία έγινε μελέτη της απόκρισης φωτοανιχνευτών οξειδίου του ψευδαργύρου σε επίπεδο και μικροδομημένο υπόστρωμα πυριτίου. Η μικροδόμηση του πυριτίου έγινε με παλμούς laser διάρκειας nanosecond.Η ικανότητα ανίχνευσης των μικροδομημένων δειγμάτων είναι σημαντικά ενισχυμένη σε όλο το φάσμα χάρη στην αύξηση της ειδικής επιφάνειας.	el
heal.advisorName	Χατζηθεοδωρίδης, Ηλίας	el
heal.committeeMemberName	Χατζηθεοδωρίδης, Ηλίας	el
heal.committeeMemberName	Μπουρουσιάν, Μιρτάτ	el
heal.committeeMemberName	Κόλλια, Κωνσταντίνα	el
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Χημικών Μηχανικών	el
heal.academicPublisherID	ntua
heal.numberOfPages	108 σ.	el
heal.fullTextAvailability	true