Atomic layer deposition of molybdenum sulfide for piezoelectric application

• Main Author: Adnan Faishal Taufiq
• Other Authors: Alfred Tok Iing Yoong
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials::Microelectronics and semiconductor materials::Thin films
• Online Access: https://hdl.handle.net/10356/166788
• Institution: Nanyang Technological University

The development of piezoelectric materials has attracted significant attention to their potential applications in various field such as sensors and energy harvesting materials. Among piezoelectric materials, Molybdenum Sulfide (MoS2) has emerged as a top candidate in flexible devices with their unique mechanical and electrical properties. In this report, we review the fabrication process and characterization of MoS2 as a piezoelectric sensor, embedded on a robotic gripper which will be used in vertical farming industry to alleviate the heavy and expensive labor in agriculture. MoS2 was prepared using a thin-film deposition technique called Atomic Layer Deposition (ALD) to deposit Molybdenum Trioxide (MoO3) before an annealing and sulfurization process using sulfur powder. Through the characterization result, different depositing route has inherently brought different unique results. After comparison, we found that using Molybdenum Hexacarbonyl (Mo(CO)6) and Ozone (O3) as precursors with an ALD window of 155℃-165℃ was the best depositing route. Post-annealing treatment has shown to control the phase constitution of MoO3 depending on the temperature and time used. Different constitution of MoO3 can be sulfurized to MoS2 successfully with different crystalline quality. A mixture of both α and β phase MoS2 is seen to be the most crystalline film out of the three distinct constitutions. Recommendations are provided from realization made during the experiments to improve fabrication and characterization of the MoS2. This project has a 5-year timeline with this research being the first year. Therefore, the results can be used as an initiation to continue with the project.