Thematic area of your work: Nanostructured surfaces 

Si nanowires for delta rhythm generator
Ostrovska K.O. 1, Druzhinin A.A. 2, Ostrovskii I.P. 1,2, Liakh-Kaguy N.S. 2
1Ivan Franko National University of Lviv. 1 Universytetska st., Lviv-79000, Ukraine.
E-mail: katerynaostrova@gmail.com 

 2 Lviv Polytechnic National University. 12 Bandery st., Lviv-79013, Ukraine. 
E-mail:druzh@polynet.lviv.ua

Delta rhythms are low frequency (0.5-4 Hz) high-amplitude waves of the brain human activity, which are dominant during sleeping. The investigations of [1] supported fascinating hypothesis that brain responses synchronized by the slow oscillation restore microwake-like activity patterns that facilitate neuronal interactions. Besides, high amplitude delta rhythms are observed at the period of wakefulness in the people with mental disabilities that could be explained by compensatory abilities of human body to suppress disordered high frequency waves.
The present paper deals with design of low frequent generator of delta rhythms based on Si nanowire. Simple design in the form of a cross-shaped growth of silicon wires allows to simulate delta rhythms when applied to the human head and to achieve a therapeutic effect.
Si wires were obtained by crystallization from the gas phase through the liquid phase due to VLS mechanism. The wire diameter was about 50-100 nm. The investigation of U-I characteristics of Si nanowire joints have shown interesting properties. Current applied to the longitudinal branch of the joint is about of 10 mA, while voltage of the transverse branch achieves to hundred mV. When current achieves the value greater than 10 mA, spontaneous voltage oscillations occur, which have periodic character. One can obtain the period of oscillations that is about of 1 Hz. It is curious, that the amplitude and the period of oscillations are the similar as in delta rhythms of human brain activity. The investigations of U-I characteristics of the joint of wires with various diameters have shown size dependence of the period in the range 1-3 Hz and amplitude of oscillations, which is increased in 20% when the diameter falls down from 100 to 50 nm. Possible mechanisms of the observed oscillations are discussed. 

1.	Dang-Vu T., Schabus M., Desseilles M., Albouy G., Boly M. Spontaneous neural activity during human slow wave sleep // Proceedings of the National Academy of Sciences. – 2008.- 105. N39. - P.15160-15165.