Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 14 of 14 for “"photocurrent spectroscopy"”.
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Probing localized states distributions in semiconductors by Laplace transform transient photocurrent spectroscopy
The structure of the thesis is as follows:<br/><br/>Chapter I addresses the question of how the disorder of non-crystalline semiconductors influences their electronic properties. The concept of the mobility edge and mobility gap is introduced and a definition of the density of electronic states …
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Photocurrent Spectroscopy Study of Graphene / Hexagonal Boron Nitride Moiré Superlattice In the Far-Infrared Regime
… a method named Fourier-transform infrared (FTIR) photocurrent spectroscopy. I will discuss the advantage of this method, and why it is suitable for far-infrared studies of 2D materials. Then I will apply it to the monolayer graphene / hexagonal boron nitride (hBN) moiré superlattices, where I …
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Investigating the nature of passive films on austenitic stainless steels
… solution were characterised by in situ Raman spectroscopy and photocurrent spectroscopy coupled with electrochemical measurements.
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Photon-induced tunneling in graphene-boron nitride-graphene heterostructures
… nitride-graphene heterostructures. Scanning photocurrent spectroscopy allows us to explore the tunneling behavior of these devices as a function of both photon energy and bias voltage. Tunneling through the boron nitride insulator is found to be dramatically enhanced by the presence of light, …
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Ultrafast Spectroscopic Studies of Solution-Processing Organic Photovoltaic Materials and Devices
… namely temperature-dependent pump-push photocurrent spectroscopy, which is able to measure the strength of interaction between charges in working OSCs. This technique is applied to research which factors govern the dissociation of molecular excited states in fullerene-based blends. …
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Optoelectronics of graphene-based Van der Waals heterostructures
… nanoscale fabrication and microscale photocurrent spectroscopy and imaging. In Chapter 1, 1 will briefly discuss basic physical properties of the vdW materials involved in this thesis and introduce the main nanofabrication and measurement techniques. Chapter 2-4 are about hot electron …
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Unipolar barrier strained layer superlattice infrared photodiodes : physics and barrier engineering
… the nature of minibands. Polarization sensitive photocurrent spectroscopy measurements were carried out on MWIR and LWIR T2SL material, and experimental results were correlated with the theoretical simulations to unambiguously establish the ordering of valence minibands in T2SL system. It was …
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Defects and Ionic Transport at Reduced Temperatures -- Electric Field and Optical Control on Nanoscopic Spatial Scales
… and are supported by a combination of impedance spectroscopy (IS) and intensity-modulated photocurrent spectroscopy (IMPS).
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Self-assembled Plasmonic Nanostructures for Thin Film Photovoltaics
… involving a combination of phothermal de ection spectroscopy and fourier transform photocurrent spectroscopy, employed for substrate con guration lms allowed for the quanti cation of useful and parasitic absorption. It is demonstrated that the optical losses in the NPs are insigni cant in the …
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Spatially Resolved Charge Transport and Recombination in Metal-Halide Perovskite Films and Solar Cells
Metal-halide perovskites show great promise as solution-processable semiconductors for efficient solar cells and LEDs. In particular, the diffusion range of photogenerated carriers is unexpectedly long and the luminescence yield is remarkably high. While much effort has been made to improve device …
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Electrochemical and Photoelectrochemical Study of Conduction modes in Nanostructured TiO2 Films
… The results of EIS (Electrochemical Impedance Spectroscopy) mainly showed the presence of a barrier layer (junction metal/semiconductor or metal/oxide/semiconductor) between the TiO2 layer and the stainless steel in the absence and presence of niobium. The carrier density is estimated at almost …
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Carbon Nitride and Conjugated Polymer Composite Materials
… function as an acceptor material improving the photocurrent generation both in solution and in solid state photovoltaic devices, with the external quantum efficiencies reaching 1% at high nitrogen contents. The occurrence of the donor–acceptor charge transfer was further evidenced by suppression …
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Elektrische Modellierung und Vermessung von farbstoffsensibilisierten Solarzellen , Ein analytisches Modell zur Berechnung der stationären Kennlinien und Impedanzen
Es wird ein analytisches Modell der farbstoffsensibilisierten Solarzelle <br>(FSZ) entwickelt, welches erlaubt, aus den physikalischen Parametern der <br>FSZ (Zelldicke, Diffusionskonstanten und mittlere Lebensdauern der <br>Ladungsträger, Elektrolyt-Konzentration, etc. ...) sowohl das …