WIDTH OF ENERGY BAND GAP OF NANOPOROUS SEMICONDUCTOR FILMS

The aim of this work is to experimentally clarify the reasons for the appearance of jumps in the current and memory of semiconductor nanoporous structures.Porous nanostructures were obtained by electrochemical etching. The current-voltage characteristics of the samples were measured for porous silicon and on thin films of a chalcogenide glassy semiconductor. The existence of jump-like switching and current hysteresis in porous silicon nanofilms under laser illumination is shown experimentally.A connection between the switching voltage values and the dependence of the band gap on the porosity of nanofilms is found. These results make it possible to construct a theory of current switching and its hysteresis based on the concepts of the theory of second-order phase transitions.

Структура халькогенидного стеклообразного полупроводника Se-=SUB=-95-=/SUB=-As-=SUB=-5-=/SUB=-, легированного примесью EuF-=SUB=-3-=/SUB=-

The local structure of film samples of chalcogenide glassy semiconductor Se95As5 and Se95As5(EuF3)x (x = 0.01 ÷ 1 at%) have been studied by X-ray diffraction and Raman scattering. The ‘‘quasi-period’’ of the structure, the correlation length, the structural elements and chemical bonds that form the amorphous matrix of the materials studied have been determined. Interpretation of results obtained has been carried out within the framework of the Elliot voidscluster model, taking into account the chemical activity of europium ions.

Влияние примеси самария на локальную структуру халькогенидного стеклообразного полупроводника Se-=SUB=-95-=/SUB=-Te-=SUB=-5-=/SUB=- и механизм прохождения тока через структуры Al-Se-=SUB=-95-=/SUB=-Te-=SUB=-5-=/SUB=-<Sm>-Te

Effect of samarium doping on the local structure and morphological features of films surface of the Se95Te5 chalcogenide glassy semiconductor system have been investigated by X-ray analysis and atomic force microscopy methods, and the influence of doping on the current passing mechanism through the Al-Se95Te5 <Sm> -Te structures have been also considered by measuring the current-voltage characteristics in a stationary mode. The results obtained are interpreted on the basis of the theory of Lampert injection currents, the Elliott void-cluster model and the Mott and Street charged defect model proposed for chalcogenide glasses.