Bandgap Engineering of 2D Materials toward High-Performing Straintronics.

Straintronics leverages mechanical strain to alter the electronic properties of materials, providing an energy-efficient alternative to traditional electronic controls while enhancing device performance. Key to the application of straintronics is bandgap engineering, which enables tuning of the energy difference between the valence and conduction bands of a material to optimize its optoelectronic properties. This mini-review highlights the fundamental principles of straintronics and the critical role of bandgap engineering within this context. It discusses the unique characteristics of various two-dimensional (2D) materials, such as graphene, transition metal dichalcogenides (TMDs), hexagonal boron nitride (h-BN), and black phosphorus, which make them suitable for strain-engineered applications. Detailed examples of how mechanical deformation can modulate the bandgap to achieve desired electronic properties are provided, while recent experimental and theoretical studies demonstrating the mechanisms by which strain influences the bandgap in these materials are reviewed, emphasizing their implications for device fabrication. The review concludes with an assessment of the challenges and future directions in the development of high-performing straintronic devices, highlighting their potential applications in flexible electronics, sensors, and optoelectronics.