Effects of Measurements Conditions on an Extended-Gate FET used as pH sensor

Fernandes, Jessica Colnaghi; Nascimento, Raphael Aparecido Sanches; Mulato, Marcelo

doi:10.1590/1980-5373-mr-2015-0248

Cited by 8 publications

(3 citation statements)

References 40 publications

(43 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, when biomedical applications are targeted with long‐term monitoring (approximately in hours), the surface modification of the sensing membrane becomes crucial. Reported pH sensing membranes with the response times in the order of few minutes might experience surface modifications even during the calibration phase. This highlights the importance of assessing the pH sensing membrane's surface integrity during calibration and in the real application environment.…”

Section: Introductionmentioning

confidence: 99%

A Protocol to Characterize pH Sensing Materials and Systems

et al. 2018

View full text Add to dashboard Cite

Although significant progress is made in identifying pH sensing materials and device configurations, a standard protocol for benchmarking performance of next-generation pH devices is still lacking. In particular, key properties of characterization systems, such as inherent component contributions, time plots for extended-gate field-effect transistor (EGFET) measurements, and the input resistance (R in ), often go unreported in studies of pH sensing systems. These properties strongly influence the characterization system and can lead to mistaken attribution of properties to the device. In this paper, a series of essential characterization tests and parameters are reported to evaluate pH systems, such as the zinc oxide EGFET, in a standardized protocol. This EGFET ZnO sensor has a sensitivity of −58.1 mV pH −1 , drift range from 2.5 to 14.2 µA h −1 , and response time of 136 s. By using a ZnO sensing electrode, it is demonstrated that i) intrinsic contributions of reference electrode and commercial transistor (for EGFET) are not negligible; ii) time plots for EGFET configuration and defining a critical point at the onset of drift are essential for accurate sensitivity, response time, and drift reporting; and iii) the results of the pH sensing system are strongly dependent on the input resistance of the used characterization instruments. pH Sensor Benchmarking

show abstract

Section: Introductionmentioning

confidence: 99%

A Protocol to Characterize pH Sensing Materials and Systems

et al. 2018

View full text Add to dashboard Cite

show abstract

“…1 This method has drawn significant interest by providing many important advantages such as flexibility to miniaturization, cost-effectiveness, disposability, and real-time measurement.…”

Section: Introductionmentioning

confidence: 99%

“…This arrangement has better long-term stability due to the MOSFET (electronic part) protected from the potentially harmful ionic solution while the extended gate (the sensitive part) which is located in the solution is easy to replace. 1,9 However, boththe ISFET and EGEFET structures need reference electrodes in order to provide a defined reference potential. 3,9,10 Unfortunately, commercial reference electrodes are fragile, bulky, expensive, and too large for small-volume solution applications.…”

Section: Introductionmentioning

confidence: 99%

Interdigitated Extended Gate Field Effect Transistor Without Reference Electrode

Ali

2016

Journal of Elec Materi

View full text Add to dashboard Cite

An interdigitated extended gate field effect transistor (IEGFET) has been proposed as a modified pH sensor structure of an extended gate field effect transistor (EGFET). The reference electrode and the extended gate in the conventional device have been replaced by a single interdigitated extended gate. A metal-semiconductor-metal interdigitated extended gate containing two multi-finger Ni electrodes based on zinc oxide (ZnO) thin film as a pHsensitive membrane. ZnO thin film was grown on a p-type Si (100) substrate by the sol-gel technique. The fabricated extended gate is connected to a commercial metal-oxide-semiconductor field-effect transistor device in CD4007UB. The experimental data show that this structure has real time and linear pH voltage and current sensitivities in a concentration range between pH 4 and 11. The voltage and current sensitivities are found to be about 22.4 mV/pH and 45 lA/pH, respectively. Reference electrode elimination makes the IEGFET device simple to fabricate, easy to carry out the measurements, needing a small volume of solution to test and suitable for disposable biosensor applications. Furthermore, this uncomplicated structure could be extended to fabricate multiple ions microsensors and lab-on-chip devices.

show abstract