scholarly journals The theory of crystal rectifiers

1939 ◽  
Vol 171 (944) ◽  
pp. 27-38 ◽  
Keyword(s):  
Copper Oxide ◽  
Oxide Layer ◽  
Cuprous Oxide ◽  
Copper Plate ◽  
Significant Part ◽  
Lead Plate

It has long been known that the contact between a metal and a semiconductor has a resistance which varies, in many cases considerably, with the direction of the current. A well-known example is the copper-cuprous oxide rectifier, which consists of a copper plate on which a layer of cuprous oxide has been formed, the oxide being in contact with a lead plate. It is the purpose of this paper to criticize existing theories of this effect and to suggest a new one. In any crystal rectifier we have two contacts to consider; for instance, in the copper-oxide rectifier there is the contact between the copper and the oxide, and that between the oxide and the lead. We may say at once that a condition for rectification is that at least one of these contacts shall have a resistance which is not small compared with the resistance of the oxide layer; for any theory will give, in the limit of small voltages across the contact, equal resistances in both directions; it is necessary that a significant part of the fall in potential in the rectifier should occur at the contact.

scholarly journals Chromatic Change in Copper Oxide Layers Irradiated with Low Energy Ions

2021 ◽  
Author(s):  
Takuya Kobayashi ◽  
Fumitaka Nishiyama ◽  
Katsumi Takahiro
Keyword(s):  
Copper Oxide ◽  
Oxide Layer ◽  
Significant Loss ◽  
Copper Plate ◽  
Low Energy ◽  
Nuclear Reaction Analysis ◽  
Photoemission Spectrum ◽  
Satellite Line ◽  
Copper Valence ◽  
Low Energy Ions

The color of a thin copper oxide layer formed on a copper plate was transformed from reddish-brown into blue-purple by irradiation with 5 keV Ar+ ions to a fluence as low as 1 1015 Ar+ cm–2. In the unirradiated copper oxide layer, the copper valence state of Cu2+ as well as Cu+ and/or Cu0 was included as indicated by the presence of a shake-up satellite line in a photoemission spectrum. While for the irradiated one, the satellite line decreased in intensity, indicating that irradiation resulted in the reduction from Cu2+ to Cu+ and/or Cu0. Furthermore, nuclear reaction analysis using a 16O(d, p)17O reaction with 0.85 MeV deuterons revealed a significant loss of oxygen (51015 O atoms cm–2) in the irradiated layer. Thus, the chromatic change observed in the present work originated in the irradiation-induced reduction of a copper oxide.

Investigations on the Photoprotection Ability of TiO2 Coated on Copper

2005 ◽  
Vol 475-479 ◽  
pp. 297-300
Author(s):  
Raghavan Subasri ◽  
Tadashi Shinohara
Keyword(s):  
Copper Oxide ◽  
Oxide Layer ◽  
Electrode Potential ◽  
Prolonged Exposure ◽  
Electrolyte Solutions ◽  
Copper Plate ◽  
Tio2 Coating ◽  
Uv Illumination ◽  
Photogenerated Electrons ◽  
Ito Glass

A TiO2 coating when directly applied on copper plate showed an instantaneous ptype behavior, i.e. ennoblement of electrode potential on ultraviolet (UV) illumination though a copper plate when galvanically coupled to an ITO glass coated with TiO2 showed immediate lowering of electrode potential (‘n’-type effect) on illumination under deaerated conditions. The instantaneous p-type effect in the former case was attributed to the presence of a copper oxide layer present between the copper plate and the TiO2 coating. However, a prolonged exposure of the TiO2 coated copper plate showed an n-type effect under illumination after nearly 24 h, following which the electrode potential appeared stable and highly negative. This observation indicated that the photogenerated electrons in TiO2 are capable of reducing the copper oxide layer to ultimately realize the n-type effect of TiO2. The n-type effect could not be observed in aerated electrolyte solutions. The effect of different conditions in the ambience on the photoeffect of copper coated TiO2 will be discussed.

scholarly journals Chromatic Change in Copper Oxide Layers Irradiated with Low Energy Ions

2021 ◽  
Vol 5 (1) ◽  
pp. 7
Author(s):  
Takuya Kobayashi ◽  
Fumitaka Nishiyama ◽  
Katsumi Takahiro
Keyword(s):  
Copper Oxide ◽  
Oxide Layer ◽  
Significant Loss ◽  
Copper Plate ◽  
Nuclear Reaction Analysis ◽  
Photoemission Spectrum ◽  
Satellite Line ◽  
Copper Valence ◽  
Low Energy Ions ◽  
Dark Blue

The color of a thin copper oxide layer formed on a copper plate was transformed from reddish-brown into dark blue-purple by irradiation with 5 keV Ar+ ions to a fluence as low as 1 × 1015 Ar+ cm−2. In the unirradiated copper oxide layer, the copper valence state of Cu2+ and Cu+ and/or Cu0 was included as indicated by the presence of a shake-up satellite line in a photoemission spectrum. While for the irradiated one, the satellite line decreased in intensity, indicating that irradiation resulted in the reduction from Cu2+ to Cu+ and/or Cu0. Furthermore, nuclear reaction analysis using a 16O(d, p)17O reaction with 0.85 MeV deuterons revealed a significant loss of oxygen (5 × 1015 O atoms cm−2) in the irradiated layer. Thus, the chromatic change observed in the present work originated in the irradiation-induced reduction of a copper oxide.

scholarly journals Photoluminescence properties of cuprous phosphide prepared through phosphating copper with a native oxide layer

RSC Advances ◽  
2021 ◽  
Vol 11 (54) ◽  
pp. 34095-34100
Author(s):  
Xue Peng ◽  
Yanfei Lv ◽  
Li Fu ◽  
Fei Chen ◽  
Weitao Su ◽  
...  
Keyword(s):  
Oxide Layer ◽  
Cuprous Oxide ◽  
Fluorescence Properties ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Photoluminescence Properties ◽  
Band Bending ◽  
Carrier Traps

The presence of cuprous oxide results in band bending at the interface between cuprous phosphide and cuprous oxide, forming carrier traps, which improves the fluorescence properties of cuprous phosphide.

Fabrication and Characterization of Heterojunction Based on a Copper Oxide Layer

2021 ◽  
Author(s):  
Oleksii Diachenko ◽  
Anatoliy Opanasyuk ◽  
Tetiana Protasova ◽  
Patrik Novak ◽  
Jaroslav Kovac
Keyword(s):  
Copper Oxide ◽  
Oxide Layer ◽  
Fabrication And Characterization

Engineering Nanowire Array Structure of Copper Oxide/Cuprous Oxide for Enhanced Oxygen Evolution Reaction

2020 ◽  
Vol 167 (2) ◽  
pp. 022508
Author(s):  
Wenjing Yuan ◽  
Yaoyao Wu ◽  
Chihhsiang Fang ◽  
Xiaodan Wang ◽  
Xiaomin Huang ◽  
...  
Keyword(s):  
Copper Oxide ◽  
Oxygen Evolution ◽  
Cuprous Oxide ◽  
Oxygen Evolution Reaction ◽  
Nanowire Array ◽  
Array Structure

Catalytic properties of Pd nanoparticles supported on Cu2O microspheres for hydrogen peroxide electroreduction

RSC Advances ◽  
2015 ◽  
Vol 5 (66) ◽  
pp. 53320-53325 ◽  
Author(s):  
Limei Sun ◽  
Shuaishuai Zhang ◽  
Wuyunga Bao ◽  
Wurigamula He
Keyword(s):  
Hydrogen Peroxide ◽  
Copper Oxide ◽  
Cuprous Oxide ◽  
Catalytic Properties ◽  
Catalyst Activity ◽  
Pd Nanoparticles ◽  
Chemical Approach ◽  
Wet Chemical ◽  
Hydrogen Peroxide Electroreduction

Cu2O was synthesized by a wet-chemical approach, and Pd electrocatalysts supported on cuprous oxide (Pd/Cu2O) and Vulcan XC-72 (Pd/C) were synthesized. The Pd/Cu2O catalyst comprised copper oxide and metallic Cu, improving the catalyst activity for H2O2 electroreduction.

n-Type Cu2O/α-Fe2O3 Heterojunctions by Electrochemical Deposition: Tuning of Cu2O Thickness for Maximum Photoelectrochemical Performance

2018 ◽  
Vol 232 (9-11) ◽  
pp. 1551-1566 ◽  
Author(s):  
Soniya Gahlawat ◽  
Nusrat Rashid ◽  
Pravin P. Ingole
Keyword(s):  
Oxide Layer ◽  
Electrochemical Deposition ◽  
Cuprous Oxide ◽  
Electrochemical Impedance ◽  
Base Material ◽  
Morphological Characteristics ◽  
Linear Sweep Voltammetry ◽  
Photoelectrochemical Performance ◽  
Photoelectrochemical Activity ◽  
X Ray

Abstract Here, we report the enhanced photoelectrochemical performance of surface modified hematite thin films with n-type copper oxide nanostructures (Cu2O/Fe2O3) obtained through simple electrochemical deposition method. The thickness and amount of cuprous oxide layer were varied by simply changing the number of electrodeposition cycles (viz. 5, 10, 25, 50 and 100) in order to understand its thermodynamic and kinetic influence on the photoelectrochemical activity of the resultant nano-heterostructures. Structural and morphological characteristics of the obtained Cu2O/Fe2O3 films have been studied by absorption spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy analysis. Electrochemical investigations such as linear sweep voltammetry, Mott–Schottky analysis, and electrochemical impedance spectroscopy suggested the formation of n-type Cu2O layers over the hematite films with varying charge-carrier densities, ranging from 0.56×1019 to 3.94×1019 cm−3, that varies with the number of cycles of electrochemical deposition. Besides, the thickness of deposited cuprous oxide layer is noted to alter the net electrochemical and photo-electrochemical response of the base material. An interesting, peak event was recorded for a particular thickness of the cuprous oxide layer (obtained after 25 cycles of electrochemical deposition) below and above which the efficiency of catalyst was impaired. The heterojunction obtained thus, followed well known Z-scheme and gave appreciable increment in the photocurrent response.

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