Piezoelectric Properties of Porous Silicon

The theoretical analysis and direct experiments with samples based on n - and p -type porous silicon demonstrate that porous silicon becomes a piezoelectric because of the reduction of the symmetry of the crystal lattice. It is shown that both n and p types of porous silicon have piezoelectric properties. The piezoelectric properties of n -type porous silicon are 2.5 times weaker than the piezoelectric properties of p -type porous silicon at the same porosity because pores in p -type silicon become wider and smoother with an increase in the distance from the surface, whereas pores in n -type porous silicon become narrower and more sinuous.