Analytical understanding of MOCVD growth and defectivity in 2D materials by Image processing

Semiconducting 2D transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) are emerging as promising materials for next-generation alternatives to Si semiconductor devices [1]. The application of 2D materials in nano-electronic devices necessitates deposition techniques capable of achieving precise layer-by-layer growth and maintaining a highly crystalline structure across entire 50mm to 300mm wafers. Currently, Chemical Vapor Deposition (CVD) is widely used as the most effective method for producing 2D layers [2].

The current state-of-the-art growth process in Metal-Organic CVD ‘MOCVD’ lacks sufficient understanding to achieve highly crystalline quality for uniform bilayer and trilayer thickness. A major gap in understanding of nucleation behaviour limits the development of consistent layer-by-layer growth of 2D layers.

In this thesis project, the focus will be on studying the nucleation and growth behavior of MoS2 on different surfaces, specifically comparing van der Waals and non-van der Waals surfaces. This study will also investigate the influence of defects, such as vacancies and stacking order, that occur during the layer-by-layer growth process. MOCVD is utilized for growth on various substrates, and the mechanical and chemical properties of these substrates affect the diffusion mechanisms of nuclei during the growth. Broadly, density and rate of formation of nuclei are crucial factors that influence diffusion and coalescence behaviour, ultimately determining the quality of the grown layers [3].

Morphological information obtained from Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) will be used to analyze the different growth processes and their respective behaviors, contributing to a better understanding of the quality of the resulting two-dimensional (2D) layers. These 2D layers are grown on substrates up to 200 mm in size, utilizing state-of-the-art cleanroom facilities and research infrastructure.

The candidate will also gain theoretical knowledge about the critical processes involved in MOCVD deposition and characterization techniques, including AFM and SEM.
[1] D. Akinwande, et al., Nature 2019, 573, 507
[2] J. Jiang, et al., Chem. Soc. Rev., 2019, 48, 4639
[3] I. Kandybka, et al, ACS Nano, 2023, 18(4), 3173-3186
 

Type of Project: Combination of internship and thesis

Master's degree:  Master of Engineering Technology; Master of Engineering Science

Master program: Chemistry/Chemical Engineering; Nanoscience & Nanotechnology; Physics; Materials Engineering

Duration: Min. 6 months

Supervisor: Annelies Delabie (Chemistry, Nano)

For more information or application, please contact the supervising scientist Pawan Kumar (pawan.kumar@imec.be).

Only for self-supporting students.