Investigating the Impact of Stress on the Optical Properties of GaN-MX[sub.2] Heterojunctions Using the First Principles

• Published in: Catalysts 2024-10, Vol.14 (10)
• Main Authors: Zhao, Xu-Cai, Dai, Meng-Yao, Lang, Fu-Mei, Zhao, Can, Chen, Qiao-Yue, Zhang, Li-Li, Huang, Yi-Neng, Lu, Hai-Ming, Qin, Xiao-Chuan
• Format: Article
• Language: English
• Subjects: Comparative analysis; Electric fields; Force and energy; Liquors; Optical properties; Technology application
• ISSN: 2073-4344; 2073-4344
• DOI: 10.3390/catal14100732

This study used the first-principles-based CASTEP software to calculate the structural, electronic, and optical properties of heterojunctions based on single-layer GaN. GaN-MX[sub.2] exhibited minimal lattice mismatches, typically less than 3.5%, thereby ensuring lattice coherence. Notably, GaN-MoSe[sub.2] had the lowest binding energy, signifying its superior stability among the variants. When compared to single-layer GaN, which has an indirect band gap, all four heterojunctions displayed a smaller direct band gap. These heterojunctions were classified as type II. GaN-MoS[sub.2] and GaN-MoSe[sub.2] possessed relatively larger interface potential differences, hinting at stronger built-in electric fields. This resulted in an enhanced electron–hole separation ability. GaN-MoSe[sub.2] exhibited the highest value for the real part of the dielectric function. This suggests a superior electronic polarization capability under an electric field, leading to high electron mobility. GaN-MoSe[sub.2] possessed the strongest optical absorption capacity. Consequently, GaN-MoSe[sub.2] was inferred to possess the strongest photocatalytic capability. The band structure and optical properties of GaN-MoSe[sub.2] under applied pressure were further calculated. The findings revealed that stress significantly influenced the band gap width and light absorption capacity of GaN-MoSe[sub.2]. Specifically, under a pressure of 5 GPa, GaN-MoSe[sub.2] demonstrated a significantly narrower band gap and enhanced absorption capacity compared to its intrinsic state. These results imply that the application of stress could potentially boost its photocatalytic performance, making it a promising candidate for various applications.