Strain-modulated electronics enabled by surface piezoelectricity.

The strain-induced polarization in a piezoelectric semiconductor is an effective strategy to modulate its current transport. However, the piezoelectricity is degraded by the free charges, and the inevitable compromise of piezoelectricity and semiconductivity severely limits the material choice and device performance. We tackle this dilemma by investigating the polarization caused by broken translational symmetry of a material surface. The ubiquitous surface piezoelectricity of solid materials enables the strain-induced polarization change to control the electrical transport effectively in crystals without bulk piezoelectricity. The Schottky barrier is shown to prohibit the bulk charges from screening the surface polarization. The strain engineering of the barrier height leads to an exponential modulation of the current, and an unprecedented gauge factor of 3.10×10⁸ and an on/off ratio of 2.53×10⁵ are demonstrated. The outstanding tunability of current with the synergistic effect of the surface piezoelectricity and metal-semiconductor contact unlocks the device development from various materials. [Display omitted] • Strain-modulated electronics is realized with a gauge factor of 3.10×10⁸ and an on/off ratio of 2.53×10⁵. • The surface piezoelectricity of a semiconductor is positively correlated with its electrical conductivity. • The charge depletion layer prevents the bulk charges from annihilating the surface polarization. [ABSTRACT FROM AUTHOR]