Selective detection of heavy metal ions by self assembled chemical field effect transistors

• Published in: Applied physics letters Vol. 106; no. 16
• Main Authors: Ruan, Hang, Kang, Yuhong, Gladwin, Elizabeth, Claus, Richard O.
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 20-04-2015
• Subjects: Applied physics; ARSENIC; CADMIUM; CESIUM; CHROMIUM; CHROMIUM IONS; CONCENTRATION RATIO; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; FIELD EFFECT TRANSISTORS; GOLD; HEAVY METALS; Ions; LAYERS; LEAD IONS; MERCURY; Mercury (metal); Metal ions; MODIFICATIONS; NANOPARTICLES; Organic chemistry; Response time; Selectivity; Self-assembly; Semiconductor devices; SEMICONDUCTOR MATERIALS; SENSORS; Transistors
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4918988

Multiple layer-by-layer sensor material modifications were designed and implemented to achieve selectivity of semiconductor based chemical field effect transistors (ChemFETs) to particular heavy metal ions. The ChemFET sensors were fabricated and modified in three ways, with the intent to initially target first mercury and lead ions and then chromium ions, respectively. Sensor characterization was performed with the gate regions of the sensor elements exposed to different concentrations of target heavy metal ion solutions. A minimum detection level in the range of 0.1 ppm and a 10%–90% response time of less than 10 s were demonstrated. By combining layer-by-layer gold nanoparticles and lead ionophores, a sensor is produced that is sensitive and selective not only to chromium but also to Cr3+ and Cr6+. This result supports the claim that high selectivity can be achieved by designing self-assembled bonding for lead, arsenic, chromium, cesium, mercury, and cadmium.