Surface Work Function of Transparent Conductive ZnO Films

Wei, Min; Li, Chunfu; Deng, Xiaojun; Hong, Dunpin

doi:10.1016/j.egypro.2012.01.014

Cited by 60 publications

(30 citation statements)

References 9 publications

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“…With respect to the clean surface case, the electrostatic potential is greatly decreased after Be doping.This may be attributed to the small atomic number of Be compared to the Zn atom, and to the large structural relaxation induced by Be-doping.The calculated work function for the clean ZnO (000 1) surface is 5.65 eV. This value is somewhat higher than the reported values in literature which they are between 4.5 eV and 5.1 eV[62][63][64][65]. This difference can be attributed directly to the presence of surface states.…”

contrasting

confidence: 67%

Hydrogen sensing properties of the ZnO(0 0 0 1¯) surface enhanced by Be doping: A first principles study

Lahmer

2015

Sensors and Actuators B: Chemical

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contrasting

confidence: 67%

Hydrogen sensing properties of the ZnO(0 0 0 1¯) surface enhanced by Be doping: A first principles study

Lahmer

2015

Sensors and Actuators B: Chemical

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“…The electrochemical electron transport through the shell region of the CdSeZnS nanoparticles is also observed by cyclic voltammogram. 56,57 In 59 This leads to work function modulated by oxidation/reduction as well as energy band bending of Si is increased/decreased. Consequence, the reference voltage is needed to do flatband of Si.…”

Section: Resultsmentioning

confidence: 99%

Highly Reliable Label-Free Detection of Urea/Glucose and Sensing Mechanism Using SiO₂and CdSe-ZnS Nanoparticles in Electrolyte-Insulator-Semiconductor Structure

Kumar

Maikap

Singh

et al. 2016

J. Electrochem. Soc.

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A simple, label-free and cost effective sensor have been studied for reliable urea/glucose sensing, and common serum analyte detection comparable with market available urea "Assay Kit" is also performed by using SiO 2 and CdSe-ZnS nanoparticles in electrolyte-insulator-semiconductor structure for the first time. Thermally grown SiO 2 membrane has shown lower pH detection limit (0.081) and lowest drift rate (2.9 mV/hr) than those of the sputtering and E-beam deposited SiO 2 membranes. The urea detection at physiological buffer pH 7.4 with sensitivity of ∼1.6 mV/mg.dl −1 at linear range of 6 to 36 mg/dl is shown. The pH detection limit is further reduced (0.074) by using chaperonin protein mediated CdSe-ZnS nanoparticles assembly over SiO 2 surface owing to high pH sensitivity of 55 mV/pH. The sensing mechanism is due to the SiO x content decreased with increasing pH value. This suggests the lower H + ions absorption on the sensing membrane surface, which is observed by X-ray photo-electron spectroscopy. The glucose concentration is detected by using the core-shell CdSe-ZnS nanoparticles through H 2 O 2 sensing because of reduction/oxidation (redox) properties of Zn as well as Zn 2+ ions generation. Due to the high catalytic activity for H 2 O 2 sensitivity, low detection limit of 1 μM is obtained, which will help to detect glucose using this bio-chip in future. The surface charge as well as potential variation of sensing membranes corresponds to ionic concentration can be used for detection of bio-molecules. [3][4][5] Basically, the pH as well as ionic concentration change (H + and OH − ) is major product of enzymatic reaction with analytes (urea, creatinine, acetylcholine, tributyrine, glucose, etc. 6-8 ), which can be measured by using electrolyte-insulator-semiconductor (EIS) structures. Among those analytes, urea and glucose are the very common potential biomarkers for diagnosis of common diseases such as heart failure, diabetes, and kidney injury. [9][10][11][12] Generally, the urea concentration has been detected through pH change. 13,14 They have reported the detection of glucose concentration by measuring the resultant pH change in presence of glucose oxidase. However, small change of pH restricts the glucose measurement at lower concentration and encourages to sense other catalysis product. Hydrogen-peroxide (H 2 O 2 ) is also a catalysis product of selective enzymatic degradation of glucose, cholesterol, lactate, and so on. [15][16][17] In this regards, the sensing membrane in EIS structure has a key role to detect pH or H 2 O 2 for easy use in our daily life with low cost. Consequently, many materials such as SiO 2 , Si 3 N 4 , Al 2 O 3 , HfO 2 , and Ta 2 O 5 have been investigated for pH sensing.18-21 Hal et al. 22 have reported the high intrinsic buffer capacity of SiO 2 at low concentrated basic pH buffer results into higher surface sites and membrane-electrolyte interface reactivity. Due to very simple structure and good interface with substrate, SiO 2 is a reliable membrane to develop urea senso...

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“…WF values from UPS measurements are generally lower (probably because affected by artifacts induced by the UV exposure) than those from theoretical models (which, on the other hand do not take into account defects such as oxygen vacancies and interstitial Zn), although both approaches yielded WF values spread in a wide range. Conversely, C–I and KPFM measurements yielded similar WF values that are also more reproducible in the range 4.6–4.95 eV for the O‐polar and in the range 4.25–4.6 eV for the Zn‐polar, while the WF of the non‐polar (01‐10) ZnO crystal has been reported in the range 4.3–4.64 eV . Calibrating our KPFM values against the WF of a reference evaporated gold contact (WF(Au) = 4.75 eV) (scheme in Figure ), we measured 4.65 ± 0.05, 4.85 ± 0.05, and 4.71 ± 0.05 eV for the untreated Zn‐polar, O‐polar and non‐polar ZnO, respectively.…”

Section: Resultsmentioning

confidence: 58%

H₂ and N₂ Remote Plasma Processing of Wurtzite‐Like Oxides: Implications for Energy Applications

Giangregorio

Bianco

Capezzuto

et al. 2015

Plasma Processes & Polymers

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Remote plasma processing is one of the most effective methods for the manipulation of intrinsic defects, doping, stoichiometry, and morphology of a large variety of oxides. Here, we discuss the interaction of polar ZnO and of LiGaO2 and LiAlO2 with atomic hydrogen and nitrogen produced by remote H2 and N2 plasmas. We show that the various crystallographic faces of those wurtzite‐like oxides are characterized by a different reactivity to hydrogen and nitrogen. Specifically, we demonstrate that the O‐polar ZnO is the most stable surface to hydrogen and, therefore, it should be the one of interest to preserve electrode stability in all those applications involving hydrogen. Conversely, we found that H2 remote plasma processing does not significantly alter Li‐based oxides LiGaO2 and LiAlO2, while their nitridation can be exploited to alter the Li composition and mobility.

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Surface Work Function of Transparent Conductive ZnO Films

Cited by 60 publications

References 9 publications

Hydrogen sensing properties of the ZnO(0 0 0 1¯) surface enhanced by Be doping: A first principles study

Hydrogen sensing properties of the ZnO(0 0 0 1¯) surface enhanced by Be doping: A first principles study

Highly Reliable Label-Free Detection of Urea/Glucose and Sensing Mechanism Using SiO₂and CdSe-ZnS Nanoparticles in Electrolyte-Insulator-Semiconductor Structure

H₂ and N₂ Remote Plasma Processing of Wurtzite‐Like Oxides: Implications for Energy Applications

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Surface Work Function of Transparent Conductive ZnO Films

Cited by 60 publications

References 9 publications

Hydrogen sensing properties of the ZnO(0 0 0 1¯) surface enhanced by Be doping: A first principles study

Hydrogen sensing properties of the ZnO(0 0 0 1¯) surface enhanced by Be doping: A first principles study

Highly Reliable Label-Free Detection of Urea/Glucose and Sensing Mechanism Using SiO2and CdSe-ZnS Nanoparticles in Electrolyte-Insulator-Semiconductor Structure

H2 and N2 Remote Plasma Processing of Wurtzite‐Like Oxides: Implications for Energy Applications

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Product

Resources

About

Highly Reliable Label-Free Detection of Urea/Glucose and Sensing Mechanism Using SiO₂and CdSe-ZnS Nanoparticles in Electrolyte-Insulator-Semiconductor Structure

H₂ and N₂ Remote Plasma Processing of Wurtzite‐Like Oxides: Implications for Energy Applications