Highly Sensitive and Fast-Response Volatile Organic Compounds Sensors Based on Star-Shaped BaTiO<sub>3</sub>/ZnO Heterostructures
Mohsen Taheripour, Navid Yasrebi, Sh. Nasresfahani, Mohammad Hossein Sheikhi
Abstract
Integrating different semiconductor materials, taking merits of each component's advantages and synergistic properties, hold great promise to enhance the performance of gas sensors. In the present study, a multistep fabrication process, involving the environment-friendly hydrothermal process and simple sol-gel techniques is proposed for the fabrication of star-shaped BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /ZnO heterostructures based sensors. Sensors with different molar ratios of BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> to ZnO were fabricated and exploited for the detection of volatile organic compounds. Characterizations of the BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /ZnO heterostructures using X-ray diffraction spectroscopy, field emission scanning electron microscopy, and energy dispersive spectroscopy provided clear evidence of high-purity star-shaped heterostructure formation. Gas sensing measurement results illustrate that the BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /ZnO heterostructure based sensor with a molar ratio of 1:2 exhibits an abrupt and reliable gas response to ethanol and acetone at the optimum working temperature of 300 °C. Moreover, the BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> /ZnO heterostructure sensor with a molar ratio of 1:3 shows a significant response to methanol at the optimum working temperature of 260 °C. The enhanced sensing characteristics of the sensor are attributed to the formation of heterojunctions at the interface of BaTiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> and ZnO and surface area enhancement provided by its star-shaped morphology.