Highly Selective H ₂ S Gas Sensing Based on InAs-ZnSe Core-Shell Quantum Dots

Indium arsenide (InAs) gas sensors are conventionally fabricated using epitaxial methods, which rely on costly equipment and are less suitable for low-cost manufacturing; therefore, the number of studies on InAs-based gas sensors has remained limited. In this paper, we report the gas-sensing properties of colloidal InAs quantum dots (QDs) and InAs-ZnSe core-shell QDs synthesized via a cost-effective and scalable hot-injection chemical route. This approach presents significant advancements and offers a practical and accessible alternative to epitaxial methods. The growth of the ZnSe shell over InAs enhances the chemical stability of QDs and improves their sensing response. Our findings demonstrate that colloidal InAs QD-based sensors show a response of 2.97 to 50 ppm H₂S gas, which remarkably enhanced to 26 under the same conditions after growing the ZnSe shell and the formation of InAs-ZnSe core-shell QDs. These findings establish the feasibility and effectiveness of colloidal III-V QDs for gas-sensing applications, offering a new low-cost pathway for developing sensors based on III-V semiconductors.