Basanta Bhowmik

This study demonstrated for the first time 3, 3-dimethylpentane detection using MoS₂ thin film transistor (TFT) and modified Ni cluster MoS₂ TFT sensor, a biomarker linked to breast cancer. The Ni clusters make the film more sensitive and selective by creating active adsorption sites and catalytic interactions. The MoS₂ film was prepared by low cost hydrothermal followed by dip coating for successfully forming Ni cluster on MoS₂/SiO₂/Si. Electrical characterizations of the Ni-MoS₂ TFT for the –1 V to 2.5 V bias window showed I_on/I_off, sub-threshold swing (SS), threshold voltage (V_t), and mobility (μ_n) as 5.3×10⁶, 67 mv/decade, 0.6 V, and 47 cm²/Vs, respectively. Under dynamic response measurements Ni-cluster modified MoS₂ surfaces demonstrated better 3, 3-dimethylpentane adsorption capability than the pristine MoS₂. 3, 3-dimethylpentane sensing showed maximum response of 79% and 59.6% at 150°C and 200°C for Ni-MoS₂ thin film and pristine MoS₂, respectively. The sensor showed fast response time of ∼5s with lower detection limits of ∼1 ppm, and good repeatability. Electrostatic gate induced adsorption-desorption of 3, 3-dimethylpentane accelerated by spill over mechanism of Ni cluster on MoS₂ surfaces were correlated considering barrier limited energy band diagram and charge transfer model.

Selectivity improvement by the frequency tuning of Mg@ZnO–TiO ₂ nanoflake-based heterojunction devices under exposure to different volatile organic compounds is the prime focus of the present paper.