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Updated: Nov 23, 2025

Nanofabrication of Gate-defined GaAs/AlGaAs Lateral Quantum Dots
Published on: November 1, 2013
Comparison of the Extended Gate Field-Effect Transistor with Direct Potentiometric Sensing for Super-Nernstian
Lujia Rao1, Peng Wang1, Yinping Qian1
1Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, People's Republic of China.
Abstract:
We systematically study the sensitivity and noise of an InN/InGaN quantum dot (QD) extended gate field-effect transistor (EGFET) with super-Nernstian sensitivity and directly compare the performance with potentiometric sensing. The QD sensor exhibits a sensitivity of -80 mV/decade with excellent linearity over a wide concentration range, assessed for chloride anion detection in 10-4 to 0.1 M KCl aqueous solutions. The sensitivity and linearity are reproduced for the EGFET and direct open-circuit potential (OCP) readout. The EGFET noise in the saturated regime is smaller than the OCP noise, while the EGFET noise in the linear regime is largest. This highlights EGFET operation in the saturated regime for most precise measurements and the lowest limit of detection and the lowest limit of quantification, which is attributed to the low-impedance current measurement at a relatively high bias and the large OCP for the InN/InGaN QDs.
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