Physico-Chemical nanomaterials science

Features of changes in the electrical resistance of p-Si crystals under the action of an elastic one-axial mechanical load and a magnetic field
R.M. Lys1, B.V. Pavlyk1, R.I. Didyk1, J.A. Shykorjak1, M.O. Kushlyk1, 2, D.P. Slobodzyan1, I.D. Karbovnyk1
1Faculty of Electronics and Computer Technologies, Ivan Franko National University of Lviv. Str. Tarnavskoho, 107, Lviv-79017, Ukraine.
2Institute of Physics PAS, Al. Lotników 32/46, Warsaw 02-668, Poland 
E-mail: lys_r@ukr.net

The investigation of the role of mechanical stresses and the magnetic field in determining the electro physical characteristics of semiconductor materials (in particular, p-Si, which crystals are model semiconductors) is relevant both in terms of using the obtained data to improve the stability of the operation of the devices, and in terms of obtaining relevant information on the piezo resistive properties of materials and structures that can be used for the development of sensitive elements of mechanical and electrical transducers.
The characteristic feature of the dependence of the p-Si sample resistance on the magnitude of its mechanical load (R(σ)) is the reduction of the resistance during compression and the  increase during the release within a single deformation cycle. The difference between the positions of the compression curves and the release curves decreases with the increase in the number of cycles.
It has been experimentally established that the increase in the magnitude of the mechanical load of the sample to 18 MPa changes the appearance of the graph R(σ). There is a sharp decrease (leap) of the resistance at the moment of transition from compression to release. This can be explained by the fact that due to the deeper and more prolonged (about 90 min) penetration of the dislocation loops, and the corresponding increase in their length, they accumulate a significant number of charged defects that remain unplaced at the beginning of the release (reduction of the field of mechanical stress).
A fluctuation of the resistance value in the direction of increase or towards the reduction occurs in the magnetic field. The diffusion of magnetically sensitive defects into the near-surface region can be explained by the repetition of the processes described in time. In a deformed crystalline lattice, diffusion processes occur more rapidly, which increases the frequency of oscillations of the resistance value.