title: Role of morphological structure, doping, and coating of different materials in the sensing characteristics of humidity sensors.
abstract: The humidity sensing characteristics of different sensing materials are important properties in order to monitor different products or events in a wide range of industrial sectors, research and development laboratories as well as daily life. The primary aim of this study is to compare the sensing characteristics, including impedance or resistance, capacitance, hysteresis, recovery and response times, and stability with respect to relative humidity, frequency, and temperature, of different materials. Various materials, including ceramics, semiconductors, and polymers, used for sensing relative humidity have been reviewed. Correlations of the different electrical characteristics of different doped sensor materials as the most unique feature of a material have been noted. The electrical properties of different sensor materials are found to change significantly with the morphological changes, doping concentration of different materials and film thickness of the substrate. Various applications and scopes are pointed out in the review article. We extensively reviewed almost all main kinds of relative humidity sensors and how their electrical characteristics vary with different doping concentrations, film thickness and basic sensing materials. Based on statistical tests, the zinc oxide-based sensing material is best for humidity sensor design since it shows extremely low hysteresis loss, minimum response and recovery times and excellent stability.
authors.affiliation: Department of Biomedical Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia. ashisbidyarthi@gmail.com.
authors.forename: Ashis
authors.initials: A
authors.lastname: Tripathy
authors.affiliation: Department of Biomedical Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia. prsumit@gmail.com.
authors.forename: Sumit
authors.initials: S
authors.lastname: Pramanik
authors.affiliation: Department of Biomedical Engineering, Inje University, Gimhae 621-749, Korea. minerva@inje.ac.kr.
authors.forename: Jongman
authors.initials: J
authors.lastname: Cho
authors.affiliation: Department of Biomedical Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia. jsanthosh@um.edu.my.
authors.forename: Jayasree
authors.initials: J
authors.lastname: Santhosh
authors.affiliation: Department of Biomedical Engineering, University of Malaya, Kuala Lumpur 50603, Malaysia. jsanthosh@um.edu.my.
authors.forename: Noor Azuan Abu
authors.initials: NA
authors.lastname: Osman
mesh_terms: D004784:Environmental Monitoring; D004867:Equipment Design; D006813:Humidity; D011108:Polymers / Q000737:chemistry*; D012666:Semiconductors; D013696:Temperature; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D011108:Polymers; D015034:Zinc Oxide