Electrical and optical properties of ZnO–WO3 nanocomposite and its application as a solid-state humidity sensor

Abstract

This study reports the humidity sensing characteristics of ZnO-WO 3 nanocomposite. Pellet samples of 0-5 weight% ZnO in WO 3 were sintered from 300 to 600 • C. When exposed to humidity, the resistance of the sensing samples was found to decrease with increase in relative humidity (RH). Five percent ZnO-doped WO 3 showed maximum sensitivity of 20.95 M /%RH in 15-95% RH range. Sensor parameters like reproducibility, aging, hysteresis, response and recovery times were also studied. Sensing mechanism is discussed in terms of sintering temperature, composition and crystallite size of the sensing element. It was observed that sensing mechanism is strongly based on annealing temperature and percentage of doping. The sensing samples have also been investigated by X-ray diffraction, scanning electron microscope (SEM) and Raman spectroscopy. The crystalline size of the sample was identified by powder X-Ray Diffraction data. The SEM analysis was used to study the surface morphology. The structure, phase and the degree of crystallinity of the materials were examined by Raman spectroscopy.

Zn2+-Doped TiO2:WO3 Films Prepared by Electrospinning and Sintering: Microstructural Characterization and Electrical Signature to Moisture Sensing

“…small variation in the measured impedance modulus values (2 − 4 %) with time, considering a fixed RH (similar to the variation observed for the undoped one), with high potential usage in moisture sensing devices. The actual obtained materials, and in particular the composition doped with 2 wt% of zinc exhibits, specifically in the high humidity range, does not only show better sensitivity, but also a linear variation of the impedance modulus, characteristics not found in other materials reported in literature [39][40][41][42]. Table 2.…”

PEMBUATAN KOMPOSIT WO3-ZnO MELALUI REAKSI PADAT-PADAT DAN KARAKTERISASINYA

“…Proses pembuatannya antara lain pencampuran selama 2 jam antara padatan WO 3 dan ZnO. Pencampuran ini dilakukan agar sampel dapat bercampur dan menjadi homogen, dimana adanya penambahan polivinil alkohol sebagai pengikat (binder) antar sampel [6]. Untuk menghilangkan pengotornya, dikeringkan campuran dan diayak agar hasil campuran lebih seragam.…”

“…o , 24,37 o , 26,619°, 28,958°, 34,10°, 34,26°, 49,88°, 55,15°dimana terdapat beberapa kemiripan pola difraksi yang menunjukkan material tersebut merupakan WO 3[6]. Hal ini disesuaikan dengan standar pola difraksi WO 3 pada data JCPDS No.…”

ZnO Metal Oxide Semiconductor in Surface Acoustic Wave Sensors: A Review

“…Another method to improve the properties of ZnO is by forming heterostructures with various other oxides, such as ZnO/WO 3 [ 144 ], ZnO/Si [ 145 , 146 ], ZnO/In 2 O 3 [ 147 ] etc. For the detection of 2-methoxyethanol, Shruthu et al [ 148 ] developed two types of sensors: based on Y 2 O 3 nanoparticles and based on Y 2 O 3 /ZnO nanocomposites.…”