ZnTe-coated ZnO nanorods: Hydrogen sulfide nano-sensor purely controlled by pn junction
Nguyễn Minh Hiếu, Do Van Lam, Trương Thị Hiên, Nguyễn Đức Chính, Nguyen Duc Quang, Nguyễn Mạnh Hùng, Cao Van Phuoc, Seung‐Mo Lee, Jong‐Ryul Jeong, Chunjoong Kim, Dojin Kim
Abstract
In this study, the double hydrothermal method is proposed as a facile approach to the synthesis of ZnTe/ZnO core–shell nanorods. The coating thickness of the p-type ZnTe is varied to adjust the junction depth in the n-type ZnO nanorods, and the conductance measurements reveal the change in the conduction path in the heterojunction structures. Structural and chemical investigations conducted using X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy confirm the hetero-nanostructure formation of ZnTe/ZnO. The role of ZnTe in H2S-gas sensing by the ZnO nanorods is discussed. The enhanced sensing performance observed with a thin ZnTe coating confirms the importance of the base resistance of the nano-transducer in achieving high response characteristics. The composite structure also demonstrates a superior sensing performance of good repeatability, stability, linearity, and gas selectivity at temperatures greater than 200 °C.