Combined Electrochemical Impedance Spectroscopy, X-ray Photoelectron Spectroscopy, and Atomic Force Microscopy study of the distinct behavior of L-cysteine-thiolate formed at p- and n-GaAs(100) electrodes in Sodium Dodecyl Sulfate solution

Lăzărescu, Valentina; Enache, Mirela; Anastasescu, Mihai; Dobrescu, Gianina; Negrilǎ, C.; Lazarescu, M. F.

doi:10.1016/j.electacta.2016.12.156

Cited by 3 publications

(6 citation statements)

References 27 publications

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“…The distinct electrochemical behavior of the p-and n-GaAs(100) electrodes covered with L-cysteine-thiolate observed in sulfuric acid solutions 9,10 pointed as well to different dopant-induced surface states as being involved in. Dopants were found to play a key role in driving the particular bonding of this organic molecule, preponderant on As sites at p-doped, and on Ga sites at the n-doped substrate, as the XPS data revealed.…”

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confidence: 99%

“…STM investigations revealed indeed that dopant atoms and antisite defects have a close relationship. [11][12][13] This conclusion was strengthened by the experiments performed in sodium dodecyl sulfate (SDS) solutions 10 which showed that anionic surfactant is involved in a chemical bond only with the Ga atoms available on L-cysteinecoated GaAs(100) electrodes, observed to be in a higher amount at the p-doped electrode.…”

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confidence: 99%

“…Given that such electronic states may control the weight of the surface Ga and As atoms, which keep their chemical individuality when they interact with the species in solution, it is of interest to investigate the dopant effects on other chemical interactions. SDS is certainly a good candidate in this respect as long as this surfactant forms a chemical bond only with Ga atoms, as XPS data 10 revealed.…”

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Surface States- and Field-Effects at GaAs(100) Electrodes in Sodium Dodecyl Sulfate Acid Solution

Enache

Negrilǎ

Anastasescu

et al. 2017

J. Electrochem. Soc.

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Sodium dodecyl sulfate (SDS) effects at the electrified p-and n-GaAs(100)/H 2 SO 4 interfaces were investigated by EIS, XPS and AFM. XPS data revealed that under the open circuit conditions, SDS adsorption on GaAs(100) results in a protective overlayer which prevents the further oxidation in air of both types of semiconductor surfaces. The dopant nature is, however, decisive for the way of bonding the surfactant molecule to the surface. At the p-doped substrate, SDS adsorbs mainly at As sites by its hydrocarbon tail and by the anion head to the Ga sites at the n-doped one. Although the surfactant behaves as a dipole under the applied potential control, the dopant type plays a key role in the SDS interaction with GaAs(100) electrodes too. EIS data evidenced that SDS interaction with n-GaAs(100) electrode brings a pronounced decrease of the capacitive contribution of the surface states and a shift of the flatband potential to less negative values, unlike the p-doped one, where no significant change in its electronic properties was observed. These results were rationalized in terms of surface states-and field-effects operating at the electrified interfaces under discussion.

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Surface States- and Field-Effects at GaAs(100) Electrodes in Sodium Dodecyl Sulfate Acid Solution

Enache

Negrilǎ

Anastasescu

et al. 2017

J. Electrochem. Soc.

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“…Among the amino acids in the biological systems, only L‐cysteine contains a free thiol moiety, and plays an important role in the physiological functions such as maintaining the stability of protein, strengthening the immune system, and delaying senescence . A low or high L‐cysteine level can have serious adverse effects on the bodily functions.…”

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confidence: 99%

Photoelectrochemical Detection of L‐Cysteine with a Covalently Grafted ZnTAPc‐Gr‐based Probe

et al. 2020

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L‐cysteine plays a vital role in organisms, and is an important biomarker for many pathological diseases that seriously affect human health. In the study, a photoelectrochemical (PEC) probe with zinc‐tetramine phthalocyanine covalently grafted to graphene oxide (ZnTAPc‐Gr) was developed for L‐cysteine detection. Graphene oxide (GO) with carboxyl was used to immobilize zinc‐tetramine phthalocyanine (ZnTAPc) with amidogen (a graft structure formed by an amide covalent bond), which could firmly immobilize ZnTAPc, thereby improving the photoelectrochemical performance and stability. L‐cysteine molecule, an electron acceptor, was specifically recognized by the PEC probe, exhibiting a decrease in the photocurrent signal. Under the optimal experimental conditions, the fabricated PEC probe exhibited excellent performance in L‐cysteine analysis within a linear range of 0.25–113 μM and a detection limit of 11.4 nM. The PEC probe showed high sensitivity, selectivity, and stability. The method described herein provides an effective strategy for PEC probe construction for L‐cysteine detection, and can also serve as a promising PEC platform for the analyses of other small molecules.

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“…The further examination of the hemin-covered GaAs electrodes by second harmonic generation, X-ray photoelectron spectroscopy and atomic force microscopy pointed to a possible change in the spin conguration of the iron ions preceding the charge transfer step originating in the mutual interactions between solvent, hemin and surface sites. 12 Since surface states and eld effects were found to depend signicantly at GaAs electrodes on both the surface orientation and the charge carrier type, [14][15][16][17] the comparison between the redox behaviour of hemin on Siand Zn-doped GaAs(100) in the same electrolyte should give a good hint about the role played by the charge carrier type in this charge transfer process. It is the aim of this paper to present the results of our electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) investigations in this respect.…”

Section: Introductionmentioning

confidence: 99%

Surface states mediated charge transfer in redox behavior of hemin at GaAs(100) electrodes

2020

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Combined Electrochemical Impedance Spectroscopy, X-ray Photoelectron Spectroscopy, and Atomic Force Microscopy study of the distinct behavior of L-cysteine-thiolate formed at p- and n-GaAs(100) electrodes in Sodium Dodecyl Sulfate solution

Cited by 3 publications

References 27 publications

Surface States- and Field-Effects at GaAs(100) Electrodes in Sodium Dodecyl Sulfate Acid Solution

Surface States- and Field-Effects at GaAs(100) Electrodes in Sodium Dodecyl Sulfate Acid Solution

Photoelectrochemical Detection of L‐Cysteine with a Covalently Grafted ZnTAPc‐Gr‐based Probe

Surface states mediated charge transfer in redox behavior of hemin at GaAs(100) electrodes

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