Evaluation of GaN and In<sub>0.2</sub>Ga<sub>0.8</sub>N Semiconductors as Potentiometric Anion Selective Electrodes

Dimitrova, Rozalina; Catalan, Lionel J.J.; Alexandrov, Dimiter; Chen, Aicheng

doi:10.1002/elan.200703936

Cited by 5 publications

(6 citation statements)

References 21 publications

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“…) and the mixed polarity of the GaN surface [12]. The adsorption of larger ions may be more hindered by the proximity of negative N-face sites on GaN, thus resulting in a less negative OCP for Br À and a more negative OCP for F À .…”

Section: Resultsmentioning

confidence: 98%

“…Similarly, in the circuit shown in Figure 6b, CPE 1sc represents the capacitance of the space charge region within the In 0.2 Ga 0.8 N semiconductor electrode, where R 1ct is the charge transfer resistance across it. Although most probably the surface of the In 0.2 Ga 0.8 N electrode also has mixed polarity, it is much more homogeneous than the surface of the GaN electrode, with no distinguishable Ga-face (or In-face) and N-face regions [12]. Therefore, no second capacitor has been added to the electrical circuit for this electrode (Fig.…”

Section: Equivalent Circuit Modelsmentioning

confidence: 98%

“…6a and b). The behavior of the space charge region in the GaN electrode is complicated by the mixed polarity of the electrode surface, since both the Ga-face and N-face of the semiconductor crystal are exposed to the solution [12]. To account for this mixed polarity, a second constant phase element, CPE 2sc , was added to model the capacitance of the regions with inversed polarity (N-face as opposed to Gaface) within the space charge layer (Fig.…”

Section: Equivalent Circuit Modelsmentioning

confidence: 99%

“…The investigation of these factors may help eliminate some of the problems associated with the application of GaN and In 0.2 Ga 0.8 N electrodes, including narrow range of linear response to changes in anionic activity, deviations of the electrode slope from the theoretical (Nerstian) value, limited reproducibility of measurements, and potential drift [12].…”

Section: Introductionmentioning

confidence: 99%

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Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

et al. 2008

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The response of potentiometric anion selective electrodes employing undoped GaN or In 0.2 Ga 0.8 N films as sensing element to detect various anions was investigated in solutions of KF, KNO 3 , KCl, HOC 6 H 4 COONa, KSCN, CH 3 COOK, KClO 4 and KBr salts. The calibration plots for the GaN and In 0.2 Ga 0.8 N semiconductor electrodes contained linear regions extending over four decades of activity change in most solutions. The structure of the GaN and In 0.2 Ga 0.8 N semiconductor electrode/ electrolyte interface was studied through electrochemical impedance spectroscopy. Analogous equivalent circuits modeling the GaN or In 0.2 Ga 0.8 N electrode/electrolyte interface were proposed and their parameters were calculated. The space charge layer of the GaN and In 0.2 Ga 0.8 N semiconductors dominated the impedance of the electrochemical system at high frequencies (> 10 kHz), whereas at low frequencies (< 10 kHz), the impedance was controlled by the diffusion of electroactive species across the layer of adsorbed ions at the surface of the electrode. Results imply a strong dependence of the electrodes performance on the adsorption capacity of tested anions.

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Section: Resultsmentioning

confidence: 98%

Section: Equivalent Circuit Modelsmentioning

confidence: 98%

Section: Equivalent Circuit Modelsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

et al. 2008

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“…Επίσης, έχει αναφερθεί ότι o κρύσταλλος GaN μετώπου Ga (+c-plane GaN), καθώς και διάφορες διατάξεις HFETs της μορφής AlGaN/GaN, αποκρίνονται στα ανιόντα και στο pH. 55,56,57,58,59,60,61,62,63 Παραδόξως, όμως, σε μια πιο πρόσφατη αναφορά γίνεται λόγος για ανάλογη απόκριση στα ανιόντα, αλλά όχι και στο pH, από τον κρύσταλλο InN μετώπου In (+c-plane InN), γεγονός που προκαλεί ιδιαίτερο ενδιαφέρον. 64 Επιπλέον, τα ΙΙΙ-νιτρίδια, και κυρίως ο κρύσταλλος +c-plane GaN, έχουν χρησιμοποιηθεί και ως μεταλλάκτες σήματος για την ανάπτυξη χημικών αισθητήρων και βιοαισθητήρων, σε μια πληθώρα παραδειγμάτων.…”

Section: ιδιότητες και εφαρμογές των ημιαγωγών Iii-νιτρίδιαunclassified

Ανάπτυξη Χημικών Αισθητήρων Και Βιοαισθητήρων Σε Ετεροδομές Και Νανοδομές III-νιτριδίων

Sofikiti¹,

Σοφικίτη²

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Chemical sensors are significant analytical instruments used for the determination of a wide variety of analytes. In comparison with other analytical methods, chemical sensors excel mainly because of their ability to monitor the analyte continuously and without destroying the sample. Additionally, due to their small size, they can be easily incorporated in automated systems, such as continuous flow systems, and perform real-time monitoring. These characteristics are very important since they account for the use of chemical sensors in field analysis and in vivo monitoring. Because of that, up to now, chemical sensors have been implemented in food and water quality control, in medical diagnosis, in environmental monitoring e.t.c. Still, the applications and the interest in the market of analytical instruments are continuously increasing, revealing the intense research activity in the field which is directly related with the great significance of chemical sensors in instrumental analysis. The use of new materials for the development of chemical sensors with improved or novel characteristics is one of the main research activities in the field. In this framework, new semiconductor materials have been studied in the last few years, for the development of chemical sensors, including the group of III-nitrides. These materials are mainly used for the development of high power and high frequency electronic devices, while they are also used in optoelectronics, since they are the only semiconductors that emit light in the blue and ultraviolet region of the spectrum. Moreover, in the last few years, this group of semiconductor materials, due to their excellent chemical inertness and also mechanical and thermal stability, has attracted great interest for their use in the development of chemical sensors. The scope of this project is to explore the use of planar and nanostructured III-nitride crystals for the development of chemical sensors and biosensors. More specifically, in addition to the most extensively studied +c-plane GaN, it is aimed to expand the research to different crystal directions, such as the non polar a-plane GaN, and to other III-nitride materials, such as the InN and InGaN Abstract 2 alloys. Moreover, the use of III-nitride nanocolumns for the development of chemical sensors and biosensors is also explored for the first time.In more detail, the first part of this work concerns a comparison study case. This advantage, along with the superior optical properties of the III-nitride nanocolumns, make these materials very promising candidates for the development of novel and more sophisticated biosensors.

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Photopolymerization of Self-Assembled Monolayers of Diacetylenic Alkylphosphonic Acids on Group-III Nitride Substrates

Shishkin

Mastro

et al. 2010

Langmuir

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This paper describes the fabrication and characterization of photopolymerizable alkylphosphonate self-assembled monolayers (SAMs) on group-III nitride substrates including GaN and Al(x)Ga(1-x)N (AlGaN; x = 0.2 and 0.25). Contact angle goniometry, visible absorption spectroscopy, and atomic force microscopy were used to assess the formation, desorption, and photopolymerization of SAMs of diacetylenic alkylphosphonic acids (CH(3)(CH(2))(n)-C[triple bond]C-C[triple bond]C-(CH(2))(m)PO(OH)(2); (m, n) = (3, 11), (6, 8), and (9, 5)). As with GaN substrates (Ito, T.; Forman, S. M.; Cao, C.; Li, F.; Eddy, C. R., Jr.; Mastro, M. A.; Holm, R. T.; Henry, R. L.; Hohn, K.; Edgar, J. H. Langmuir 2008, 24, 6630-6635), alkylphosphonic acids formed SAMs on UV/O(3)-treated AlGaN substrates from their toluene solutions in contrast to other primary substituted hydrocarbons with a terminal -COOH, -NH(2), -OH, or -SH group. Diacetylenic alkylphosphonate SAMs on group-III nitrides could be polymerized by UV irradiation (254 nm), as indicated by the appearance of a visible absorption band around 640 nm and also by their significantly reduced desorption from the surface in a 0.1 M aqueous NaOH solution. A longer UV irradiation time was required to maximize the photopolymerization of a SAM having a diacetylene group close to the terminal phosphonate moiety, probably because of the hindrance of the topochemical polymerization due to the limited flexibility of the cross-linking moieties on an atomically rough substrate surface.

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Evaluation of GaN and In_0.2Ga_0.8N Semiconductors as Potentiometric Anion Selective Electrodes

Abstract: Abstract

Cited by 5 publications

References 21 publications

Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

Ανάπτυξη Χημικών Αισθητήρων Και Βιοαισθητήρων Σε Ετεροδομές Και Νανοδομές III-νιτριδίων

Photopolymerization of Self-Assembled Monolayers of Diacetylenic Alkylphosphonic Acids on Group-III Nitride Substrates

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Evaluation of GaN and In0.2Ga0.8N Semiconductors as Potentiometric Anion Selective Electrodes

Abstract: Abstract

Cited by 5 publications

References 21 publications

Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

Impedance Study of GaN and InGaN Semiconductor Anion Selective Electrodes

Ανάπτυξη Χημικών Αισθητήρων Και Βιοαισθητήρων Σε Ετεροδομές Και Νανοδομές III-νιτριδίων

Photopolymerization of Self-Assembled Monolayers of Diacetylenic Alkylphosphonic Acids on Group-III Nitride Substrates

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Evaluation of GaN and In_0.2Ga_0.8N Semiconductors as Potentiometric Anion Selective Electrodes