Electrically Controlled High Sensitivity Strain Modulation in MoS<sub>2</sub> Field-Effect Transistors via a Piezoelectric Thin Film on Silicon Substrates
Abin Varghese, Adityanarayan H. Pandey, Pooja Sharma, Yuefeng Yin, Nikhil V. Medhekar, Saurabh Lodha
Abstract
High Resolution Image Download MS PowerPoint Slide Strain can modulate bandgap and carrier mobilities in two-dimensional (2D) materials. Conventional strain-application methodologies relying on flexible/patterned/nanoindented substrates are limited by low thermal tolerance, poor tunability, and/or scalability. Here, we leverage the converse piezoelectric effect to electrically generate and control strain transfer from a piezoelectric thin film to electromechanically coupled 2D MoS 2 . Electrical bias polarity change across the piezo film tunes the nature of strain transferred to MoS 2 from compressive (∼0.23%) to tensile (∼0.14%) as verified through Raman and photoluminescence spectroscopies and substantiated by density functional theory calculations. The device architecture, on silicon substrate, integrates an MoS 2 field-effect transistor on a metal-piezoelectric-metal stack enabling strain modulation of transistor drain current (130×), on/off ratio (150×), and mobility (1.19×) with high precision, reversibility, and resolution. Large, tunable tensile (1056) and compressive (−1498) strain gauge factors, electrical strain modulation, and high thermal tolerance promise facile integration with silicon-based CMOS and micro-electromechanical systems.