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dc.contributor.authorYeltik, Aydanen_US
dc.contributor.authorAkhavan, Shahaben_US
dc.contributor.authorDemir, Hilmi Volkanen_US
dc.coverage.spatialSan Diego, CA, USA
dc.date.accessioned2016-02-08T11:34:11Z
dc.date.available2016-02-08T11:34:11Z
dc.date.issued2014-10en_US
dc.identifier.urihttp://hdl.handle.net/11693/26731
dc.descriptionDate of Conference: 12-16 Oct. 2014
dc.descriptionConference name: 2014 IEEE Photonics Conference
dc.description.abstractSolution-processable semiconductor nanocrystals (NCs) have been widely used to create novel devices for the photovoltaic, light-emission, light-detection and biosensing applications. They are good candidates especially to develope more efficient and novel optoelectronic devices owing to the high absorption cross-section, spectral tunability, deposition easiness and low cost properties. In recent years, NC integrated photodetectors have been developed to be used in large-area light-sensing applications [1]. These NC-based photodetectors have the ability to convert an optical signal to an electrical signal using the NCs as the optical absorbers. These low-cost devices were initially operated on the basis of charge collection, where an electric field imposed on the detector dissociates the photogenerated excitons into electrons and holes, in which an electric current is produced [2]. On the other hand, as an alternative device structure, we have recently developed the light-sensitive nanocrystal skin (LS-NS) [3]. These LS-NS platforms, which were fabricated over areas up to 48 cm2, are operated on the basis of photogenerated potential buildup, as opposed to conventional charge collection. In operation, close interaction of the monolayer NCs of the LS-NS with the top interfacing contact, while the bottom one is isolated using a high dielectric spacing layer, results in highly sensitive photosensing in the absence of external bias application. Furthermore, NC monolayer of the LS-NS makes the device semi-transparent with sufficient absorption, while reducing the noise generation and dark current. In our other recent work, we also reported that, by using a thick photoactive NC layer, a much lower photovoltage buildup was observed in the LS-NSs and it was attributed to the self-absorption effect [4]. In addition, we demonstrated the sensitivity increase in the LS-NSs via the absorption enhancement of NC film with the integration of plasmonic nanoparticles [5]. However, the localized plasmonic resonance band strongly limits the observed enhancement factor and the resultant operating wavelength range. Furthermore, in the absence of an external bias in the LS-NSs, each exciton tends to remain in the NC layer, where it was created, and recombine with the photogenerated holes that accumulate at the top interfacing contact, which causes also lower voltage buildup in the device. To overcome all these problems, in this study, we propose a thin TiO2 layer as the electron-accepting material and demonstrate the first account of electron transfer in NC-based light-sensitive skins, which leads to significant broadband sensitivity enhancement in the active device architecture. Here, we prove that favorable conduction band offset aids in transferring photogenerated electrons from a monolayer of NCs to an electron-accepting layer, which is ultimately useful for photosensing platforms and the next generation of light-sensing NC devices. © 2014 IEEE.en_US
dc.language.isoEnglishen_US
dc.source.titleIEEE Photonics Conference, IPC 2014en_US
dc.relation.isversionofhttp://dx.doi.org/10.1109/IPCon.2014.6995295en_US
dc.subjectElectric fieldsen_US
dc.subjectExcitonsen_US
dc.subjectHeterojunctionsen_US
dc.subjectLight sensitive materialsen_US
dc.subjectMonolayersen_US
dc.subjectNanocrystalsen_US
dc.subjectOptoelectronic devicesen_US
dc.subjectPhotodetectorsen_US
dc.subjectPhotonicsen_US
dc.subjectPhotonsen_US
dc.subjectPhotosensitivityen_US
dc.subjectPlasmonsen_US
dc.subjectSemiconductor devicesen_US
dc.subjectTitanium dioxideen_US
dc.subjectAbsorption cross sectionsen_US
dc.subjectBiosensing applicationsen_US
dc.subjectIntegrated photodetectoren_US
dc.subjectPhotogenerated electronsen_US
dc.subjectPhotogenerated excitonsen_US
dc.subjectSelf-absorption effectsen_US
dc.subjectSemiconductor nanocrystalsen_US
dc.subjectSensitivity enhancementsen_US
dc.subjectElectronsen_US
dc.titleTiO2 assisted sensitivity enhancement in photosensitive nanocrystal skinsen_US
dc.typeConference Paperen_US
dc.departmentDepartment of Electrical and Electronics Engineeringen_US
dc.departmentDepartment of Physicsen_US
dc.departmentInstitute of Materials Science and Nanotechnology (UNAM)en_US
dc.citation.spage625en_US
dc.citation.epage626en_US
dc.identifier.doi10.1109/IPCon.2014.6995295en_US
dc.publisherIEEEen_US
dc.contributor.bilkentauthorDemir, Hilmi Volkan
buir.contributor.orcidDemir, Hilmi Volkan|0000-0003-1793-112Xen_US


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