Strain-modulated electronics enabled by surface piezoelectricity

Abstract

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.