Photoelectrochemical properties of a well-structured 1.3 nm-thick pn junction crystal

2019 ◽  
Vol 55 (31) ◽  
pp. 4586-4588 ◽  
Author(s):  
Keisuke Awaya ◽  
Akihide Takashiba ◽  
Takaaki Taniguchi ◽  
Michio Koinuma ◽  
Tatsumi Ishihara ◽  
...  
Keyword(s):  
Nickel Hydroxide ◽  
Photoelectrochemical Properties ◽  
Onset Potential ◽  
Pn Junction ◽  
Photoelectrochemical Oxidation ◽  
Pn Junctions ◽  
P Type

A 1.3 nm-thick nickel hydroxide (p-type, 0.5 nm)/titania (n-type, 0.8 nm) pn junction prepared by lamination of nanosheets improved the onset potential for photoelectrochemical oxidation and increased the photooxidation current, indicating that ultrathin pn junctions suppress the recombination of photo-generated carriers.

A new thermoelectric concept using large area PN junctions

2013 ◽  
Vol 1543 ◽  
pp. 3-8 ◽  
Author(s):  
R. Chavez ◽  
A. Becker ◽  
V. Kessler ◽  
M. Engenhorst ◽  
N. Petermann ◽  
...  
Keyword(s):  
Silicon Nanoparticles ◽  
Electrical Contacts ◽  
Large Area ◽  
Charge Generation ◽  
Thermally Induced ◽  
Pn Junction ◽  
In Series ◽  
Working Principle ◽  
Pn Junctions ◽  
P Type

ABSTRACTA new thermoelectric concept using large area silicon PN junctions is experimentally demonstrated. In contrast to conventional thermoelectric generators where the n-type and p-type semiconductors are connected electrically in series and thermally in parallel, we demonstrate a large area PN junction made from densified silicon nanoparticles that combines thermally induced charge generation and separation in a space charge region with the conventional Seebeck effect by applying a temperature gradient parallel to the PN junction. In the proposed concept, the electrical contacts are made at the cold side eliminating the need for contacts at the hot side allowing temperature gradients greater than 100K to be applied. The investigated PN junction devices are produced by stacking n-type and p-type nanopowder prior to a densification process. The nanoparticulate nature of the densified PN junction lowers thermal conductivity and increases the intraband traps density which we propose is beneficial for transport across the PN junction thus enhancing the thermoelectric properties. A fundamental working principle of the proposed concept is suggested, along with characterization of power output and output voltages per temperature difference that are close to those one would expect from a conventional thermoelectric generator.

THE EFFECT OF OXYGEN ADSORPTION ON THE CONDUCTIVITY OF PBTE FILMS.

2020 ◽  
Vol 6 (8(77)) ◽  
pp. 21-23
Author(s):  
S.N. Sarmasov ◽  
R.Sh. Rahimov ◽  
T.Sh. Abdullayev
Keyword(s):  
Spectral Region ◽  
Current Flow ◽  
Oxygen Adsorption ◽  
Tunneling Mechanism ◽  
Pn Junction ◽  
Flow Through ◽  
Pn Junctions ◽  
Effect Of Oxygen

The effect of oxygen adsorption on the conductivity of PbTe films is studied. Pn junctions based on PbTe films are photosensitive in the IR spectral region with a maximum photosensitivity of 𝜆𝑚𝑎𝑥 microns. The tunneling mechanism of current flow through the pn junction is shown.

Annealing effect on the optical and photoelectrochemical properties of lead oxide

2018 ◽  
Vol 84 (3) ◽  
pp. 30301 ◽  
Author(s):  
Wided Zerguine ◽  
Djamila Abdi ◽  
Farid Habelhames ◽  
Meriem Lakhdari ◽  
Hassina Derbal-Habak ◽  
...  
Keyword(s):  
Lead Oxide ◽  
Orthorhombic Phase ◽  
Heat Treatments ◽  
Photoelectrochemical Properties ◽  
X Ray Diffraction ◽  
Vis Spectroscopy ◽  
Size And Morphology ◽  
Two Phases ◽  
P Type ◽  
The Relationship

Effect of the annealing oxidation time of electrodeposited lead (Pb) on the phase formation of lead oxide (PbO) films is reported. The phase structure, optical properties, size and morphology of the films were investigated by scanning electron microscopy, X-ray diffraction and UV-vis spectroscopy. The relationship between structur and photoelectrochemical properties was investigated. Thin films of PbO produced via air annealing of electrodeposited lead consist of a mixture of two phases, orthorhombic (o-PbO) and tetragonal (t-PbO), that determine the material properties and effectiveness as absorber layer in a photoelectrochemical device. The proportion of tetragonal t-PbO increases for longer heat treatments. After 40 h, the sample consists mainly of tetragonal t-PbO. The p-type semiconducting behavior of lead oxide was studied by photocurrent measurements. Different heat treatments yield variations in the ratio of tetragonal to orthorhombic lead oxide that effect on device performances, where devices with a higher content of tetragonal t-PbO show higher photocurrent than with the orthorhombic phase.

Photoelectrochemical properties of CdSe quantum dot sensitized p-type flower-like NiO solar cells with different deposition layer

2016 ◽  
Vol 84 ◽  
pp. 212-217 ◽  
Author(s):  
Xiaowei Li ◽  
Ruixue Chen ◽  
Huidong Sui ◽  
Xiaoxian Yuan ◽  
Meng Li ◽  
...  
Keyword(s):  
Solar Cells ◽  
Quantum Dot ◽  
Photoelectrochemical Properties ◽  
Cdse Quantum Dot ◽  
P Type

Si1−xGex Bulk Crystals Growth and PN Junction Formation by Diffusing Phosphorus

1999 ◽  
Vol 607 ◽  
Author(s):  
S. Kato ◽  
T. Horikoshi ◽  
T. Ohkubo ◽  
T. Iida ◽  
Y. Takano
Keyword(s):  
Silicon Germanium ◽  
Bulk Crystals ◽  
Temperature Dependent ◽  
Alloy Scattering ◽  
Self Diffusion ◽  
Pn Junction ◽  
Current Voltage ◽  
Vertical Bridgman ◽  
Current Voltage Characteristics ◽  
P Type

AbstractThe bulk crystal of silicon germanium was grown by vertical Bridgman method with germanium composition, x, varying from 0.6 to 1.0. The temperature dependent variation of the mobility is indicative of alloy scattering dominantly for the bulk wafer. Phosphorus was diffused in as-grown p-type bulk wafer at 850 °C to form pn-junction, and the diffusion coefficient of phosphorus was evaluated as a function of x. The diffusion behavior of phosphorus in silicon germanium is closely correlated with the germanium self-diffusion with changing x. For specimens with lower content x, P concentration profiles indicated “kink and tail” shape, while it was not observed for higher x. For current-voltage characteristics measurement, an ideality factor was obtained.

scholarly journals Atmospheric Air Plasma Treated SnS Films: An Efficient Electrocatalyst for HER

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 462 ◽  
Author(s):  
Po-Chia Huang ◽  
Sanjaya Brahma ◽  
Po-Yen Liu ◽  
Jow-Lay Huang ◽  
Sheng-Chang Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Hydrogen Adsorption ◽  
High Plasma ◽  
Air Plasma ◽  
Atmospheric Air ◽  
Onset Potential ◽  
Active Edge ◽  
Sns Thin Films ◽  
P Type ◽  
Adsorption Desorption

Here, we demonstrate the enhanced water-splitting performance (I = 10 mA/cm2, Tafel slope = 60 mV/dec, onset potential = −80 mV) of atmospheric air plasma treated (AAPT) SnS thin films by the hydrogen evolution reaction (HER). The as prepared SnS films were subjected to Atmospheric Air Plasma Treatment (AAPT) which leads to formation of additional phases of Sn and SnO2 at plasma powers of 150 W and 250 W, respectively. The AAPT treatment at 150 W leads to the evaporation of the S atoms as SO2 generates a number of S-vacancies and Sn active edge sites over the surface of the SnS thin film. S-vacancies also create Sn active edge sites, surface p-type pinning that tunes the suitable band positions, and a hydrophilic surface which is beneficial for hydrogen adsorption/desorption. At high plasma power (250 W), the surface of the SnS films becomes oxidized and degrades the HER performance. These results demonstrate that AAPT (150 W) is capable of improving the HER performance of SnS thin films and our results indicate that SnS thin films can work as efficient electrocatalysts for HER.

scholarly journals Increased efficiency in pn-junction PbS QD solar cells via NaHS treatment of the p-type layer

2017 ◽  
Vol 110 (10) ◽  
pp. 103904 ◽  
Author(s):  
Mark J. Speirs ◽  
Daniel M. Balazs ◽  
Dmitry N. Dirin ◽  
Maksym V. Kovalenko ◽  
Maria Antonietta Loi
Keyword(s):  
Solar Cells ◽  
Pn Junction ◽  
Type Layer ◽  
P Type

scholarly journals Deep-Ultraviolet (DUV)-Induced Doping in Single Channel Graphene for Pn-Junction

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3003
Author(s):  
Asif Ali ◽  
So-Young Kim ◽  
Muhammad Hussain ◽  
Syed Hassan Abbas Jaffery ◽  
Ghulam Dastgeer ◽  
...  
Keyword(s):  
Single Channel ◽  
Field Effect Transistors ◽  
Single Layer ◽  
Charge Carrier Mobility ◽  
Radiation Environment ◽  
Pmma Layer ◽  
Laboratory Environment ◽  
Pn Junction ◽  
Deep Ultraviolet ◽  
P Type

The electronic properties of single-layer, CVD-grown graphene were modulated by deep ultraviolet (DUV) light irradiation in different radiation environments. The graphene field-effect transistors (GFETs), exposed to DUV in air and pure O2, exhibited p-type doping behavior, whereas those exposed in vacuum and pure N2 gas showed n-type doping. The degree of doping increased with DUV exposure time. However, n-type doping by DUV in vacuum reached saturation after 60 min of DUV irradiation. The p-type doping by DUV in air was observed to be quite stable over a long period in a laboratory environment and at higher temperatures, with little change in charge carrier mobility. The p-doping in pure O2 showed ~15% de-doping over 4 months. The n-type doping in pure N2 exhibited a high doping effect but was highly unstable over time in a laboratory environment, with very marked de-doping towards a pristine condition. A lateral pn-junction of graphene was successfully implemented by controlling the radiation environment of the DUV. First, graphene was doped to n-type by DUV in vacuum. Then the n-type graphene was converted to p-type by exposure again to DUV in air. The n-type region of the pn-junction was protected from DUV by a thick double-coated PMMA layer. The photocurrent response as a function of Vg was investigated to study possible applications in optoelectronics.

scholarly journals Study of the photo-adjustability of pn-junctions in photovoltaic mode coupled to photoconductors

2019 ◽  
Vol 14 (3) ◽  
pp. 1-7
Author(s):  
André Luiz Costa Carvalho ◽  
Davies William de Lima Monteiro
Keyword(s):  
Photovoltaic Cell ◽  
Alternative Solution ◽  
Output Current ◽  
Pn Junction ◽  
Light Intensities ◽  
Current Voltage ◽  
Photovoltaic Mode ◽  
Pn Junctions ◽  
Parasitic Components

We propose a photo-adjustable arrangement that electrically combines a pn-junction operating in photovoltaic mode to a suitably designed photoconductor in order to keep the output current, voltage, or both, fixed. The characteristic I-V curves of a pn-junction under different light intensities do not intersect each other, resulting in different operational points for a given load. However, the resistivity of the photoconductor also changes with light, and by connecting it in parallel to the photovoltaic cell, and exposing both to the same level of irradiance, it is possible to find a design that alters the I-V curves of the cell in such a way that they will intersect at a chosen point. That could offer an alternative solution for a stable supply to autonomous DC loads. This paper presents an example case for a silicon pn-junction, considering the presence of parasitic components.

scholarly journals Electrochemical Study of Copper Ferrite as a Catalyst for CO2 Photoelectrochemical Reduction

2018 ◽  
Vol 13 (2) ◽  
pp. 236 ◽  
Author(s):  
Kaykobad Md. Rezaul Karim ◽  
Huei Ruey Ong ◽  
Hamidah Abdullah ◽  
Abu Yousuf ◽  
Chin Kui Cheng ◽  
...  
Keyword(s):  
Sol Gel ◽  
Co2 Reduction ◽  
Linear Sweep Voltammetry ◽  
Band Gap Energy ◽  
Reduction Reaction ◽  
Electrochemical Study ◽  
Flat Band ◽  
Copper Ferrite ◽  
Onset Potential ◽  
P Type

In this work, p-type CuFe2O4 was synthesized by sol gel method. The prepared CuFe2O4 was used as photocathode catalyst for photoelectrochemical (PEC) CO2 reduction. The XRD, UV-Visible Spectroscopy (UV-Vis), and Mott-Schottky (MS) experiments were done to characterize the catalyst. Linear sweep voltammetry (LSV) was employed to evaluate the visible light (λ>400 nm) effect of this catalyst for CO2 reduction.  The band gap energy of the catalyst was calculated from the UV-Vis and was found 1.30 eV. Flat band potential of the prepared CuFe2O4 was also calculated and found 0.27 V versus Ag/AgCl. Under light irradiation in the CO2-saturated NaHCO3 solution, a remarkable current development associated with CO2 reduction was found during LSV for the prepared electrode from onset potential -0.89 V with a peak current emerged at -1.01 V (vs Ag/AgCl) representing the occurrence of CO2 reduction reaction. In addition, the mechanism of PEC was proposed for the photocathode where the necessity of a bias potential in the range of 0.27 to ~ -1.0 V vs Ag/AgCl was identified which could effectively inhibit the electron-hole (e-/h+) recombination process leading to an enhancement of CO2 reduction reactions. Copyright © 2018 BCREC Group. All rights reservedReceived: 4th July 2017; Revised: 5th November 2017; Accepted: 15th November 2017; Available online: 11st June 2018; Published regularly: 1st August 2018How to Cite: Karim, K.M.R., Ong, H.R., Abdullah, H., Yousuf, A., Cheng, C.K., Khan, M.K.R. (2018). Electrochemical Study of Copper Ferrite as a Catalyst for CO2 Photoelectrochemical Reduction. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (2): 236-244 (doi:10.9767/bcrec.13.2.1317.236-244) 

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