Search results for "Schottky barrier"

Barrier inhomogeneity in vertical Schottky diodes on free standing gallium nitride

2019

Abstract In this paper, the electrical behavior of a Ni/Au Schottky barrier on free standing GaN has been studied employing a variety of techniques and correlated with the material and interface quality. The temperature dependence of the ideality factor (n) and of the Schottky barrier height (ΦB) revealed a spatial inhomogeneity of the barrier. This behavior has been described by means of the Tung's model on inhomogeneous Schottky barriers. The origin of the barrier inhomogeneity can be likely associated to the surface quality of the GaN epilayer or to microstructure of the Ni/GaN interface.

Reducing the Schottky barrier height at the MoSe2/Mo(110) interface in thin-film solar cells: Insights from first-principles calculations

2016

Abstract We report on first-principles calculations of the properties of the MoSe2/Mo(110) interface. Due to mismatch between the lattice parameters of the two structures, different patterns can form at the interface. We have studied the formation energy and the band alignment of six patterns for the MoSe2 (0001)/Mo(110) interface and one pattern for the MoSe2 (11 2 0)/Mo(110) interface. The MoSe2 (11 2 0)/Mo(110) interface is more stable than the MoSe 2 (0001)/Mo(110) interface and in contrast to MoSe2 (0001)/Mo(110), no Schottky barrier forms at MoSe2 (11 2 0)/Mo(110). Doping with Na modifies the band alignment at the interfaces. The Schottky barrier height decreases, provided that a Na a…

Characterization of Thin Passive Film-Electrolyte Junctions. The Amorphous Semiconductor (a-SC) Schottky Barrier Approach.

2017

A detailed study of the electronic properties of thin (< 20 nm) anodic TiO2 potentiostatically grown on titanium in two different solutions is presented. The results show that the nature of the anodizing solution affects the electronic properties of the anodic film and in particular the density of electronic state (DOS) distribution. Different DOS were derived from the experimental data analyzed according to the theory of amorphous semiconductor (a-SC) Schottky barrier. It is shown that the usual non-linear and frequency dependent Mott-Schottky plots are in agreement with expected theoretical behaviour of a-SC Schottky barrier. It is shown the importance of the DOS distribution in determini…

Behaviour of Nb2O5/PPy contacts: From Schottky barriers to p-n junctions

2009

In this work, a study of the photoelectrochemical responses of Nb O /PPy contacts fabricated in both organic 2 5 and aqueous solutions is performed. From the comparison between the experimental data of PPy photodeposited on Nb O in organic and in aqueous solutions, it is evident that the medium used for the photodeposition 2 5 influences the absorption coefficient, the band gap and flat band potential values.

A DC and small signal AC model for organic thin film transistors including contact effects and non quasi static regime

2017

Abstract We present a compact model for the DC and small signal AC analysis of Organic Thin Film Transistors (OTFTs). The DC part of the model assumes that the electrical current injected in the OTFT is limited by the presence of a metal/organic semiconductor junction that, at source, acts as a reverse biased Schottky junction. By including this junction, modeled as a reverse biased gated diode at source, the DC model is able to reproduce the scaling of the electrical characteristics even for short channel devices. The small signal AC part of the model uses a transmission line approach in order to compute the impedances of the channel and parasitic regions of the device. The overlap capacit…

Electrical and photoelectrical measurements on ZnO-Nanowires coated with PEDOT:PSS for Dye-Sensitized Solar Cells

2011

ABSTRACTDye-sensitized solar cells composed of an n-doped ZnO nanowire array and a p-doped polymer layer appears to be a promising candidate for low-cost production of environment-friendly solar cells. In this work, we investigate hybrid devices consisting of a transparent conducting oxide (TCO) substrate, ZnO-nanowires (ZnO-NW) or a sol-gel prepared ZnO layer, a ruthenium dye (N719) and a PEDOT:PSS or P3HT layer. The dense polycrystalline ZnO layer is able to prevent short circuits, which have a strong effect on the performance of the solar cells. This is demonstrated by the use of only the ZnO layer which improves the open circuit voltage by a factor of 2 and the efficiency by a factor of…

Investigation of amorphous oxide film-electrolyte junctions by AC techniques

1992

Current AC (alternating current) techniques are used often to characterize the energetics at a semiconducting solid phase/electrolyte interface. For thin layers having a strongly disordered or amorphous structure (such as oxide-passive layers anodically grown on valve metals), interpretative models currently used for crystalline semiconductors may produce misleading data. A new interpretation of the admittance data, based on recent models for amorphous semiconductors (a-Sc) Schottky barriers, is presented for passive films of Nb, W and Ti. The physical bases of the model are presented as well as its advantages and disadvantages. The new theory views the solid/electrolyte interface more sati…

Internal photoemission in solar blind AlGaN Schottky barrier photodiodes

2005

We have analyzed the photoresponse of solar blind AlGaN Schottky barrier photodiodes below the alloy band gap energy, in the 3.5-4.5 eV range, and we show that it is dominated by internal photoemission. The n-type Schottky barrier height is shown to increase linearly with the band gap energy of the AlGaN alloy. The amplitude of the internal photoemission signal is about 20 times smaller than the value given by the Fowler theory based on a free electron model. We explain this result by taking into account the interband transitions and the ballistic transport of photoexcited electrons in the metal. This low value of internal photoemission allows us to achieve a spectral rejection ratio betwee…

Tribovoltaic Device Based on the W/WO3 Schottky Junction Operating through Hot Carrier Extraction

2021

Current injection from metal to MoS2 probed at nanoscale by conductive atomic force microscopy

2016

Contacts with MoS2 are currently the object of many investigations, since current injection through metal/MoS2 interfaces represents one of the limiting factors to the performance of MoS2 thin film transistors. In this paper, we employed conductive atomic force microscopy (CAFM) to investigate the current injection mechanisms from a nanometric contact (a Pt coated tip) to the surface of MoS2 thin films exfoliated on SiO2. The analysis of local current-voltage (I-V) characteristics on a large array of tip positions provided high spatial resolution information on the lateral homogeneity of the tip/MoS2 Schottky barrier Phi(B) and of the ideality factor n. From the histograms of the measured P…