Open AccessComparison of the Extended Gate Field-Effect Transistor with Direct Potentiometric Sensing for Super-Nernstian InN/InGaN Quantum Dots
Author(s) -
Lujia Rao,
Peng Wang,
Yinping Qian,
Guofu Zhou,
R. Nötzel
Publication year - 2020
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.0c05364
Subject(s) - linearity , quantum dot , transistor , materials science , detection limit , sensitivity (control systems) , noise (video) , analytical chemistry (journal) , optoelectronics , field effect transistor , aqueous solution , chemistry , voltage , physics , electronic engineering , chromatography , quantum mechanics , artificial intelligence , computer science , engineering , image (mathematics)
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.