1. Introduction and Literature Review

The piezoresistance is defined as the change in electrical resistance of a material under external mechanical strain or stress, which was discovered by Smith in 1954 (Barlian et al., Proc IEEE, 97(3):513–552, 2009, [1]). Since then, a great number of research works have been relentlessly carried out to elucidate the phenomenon in numerous materials. Besides fundamental investigation, applications of the piezoresistive effect in semiconductors can be found in numerous Micro Electro Mechanical Systems (MEMS) sensors, thanks to its superior properties, including device miniaturization, simple readout circuit, and low power consumption (Eaton and Smith, Smart Mater Struct, 6:530–539, 1997, [2]; Kumar and Pant, Microsyst Technol, 20(7):1213–1247, 2014, [3]), compared to other sensing technologies (e.g. electrostatic, piezoelectric and optical).