عنوان المقالة:الخصائص البصرية والكهربائية لأغشية السيلينيوم النقية وغير المتبلورة Optical and electrical properties of pure and doped amorphous thin selenium films
SALWAN K. J. AL-ANI, MEHDI N. AL-DELAIMI ALI H. ABDUL MUNAIM and HABIBA M. JAWHER:
Abstract
Thin amorphous selenium (a-Se) films and Se films doped with indium have been prepared by thermal evaporation under high vacuum and controlled deposition conditions. Measurement of DC conductivity made in situ as a function of temperature (in the range room temperature to 400K) and absorption in the photon energy range to 6•5eV are reported. The effects of film thickness from 50 to 760 nm and vacuum annealing on these properties are considered. Our specimens showed low conductivity and two activation energies indicating different conduction mechanisms in the gap. Furthermore, the conductivity is found to be independent of thickness but sensitive to doping and oxygen incorporation. The value of the optical energy gap (Eopt) is (2•0 and for (a-Se) and (a-Se : In) films, respectively. From the Urbach edge, the value of Ee, the width of the tail of the localized states in the gap, is estimated. The values of both Eopt and Ee are nearly independent of thickness. A preliminary study of the infra-red transmission is also investigated. The value of the refractive index is in the range
ا.د سلوان كمال جميل العاني | Prof.Salwan K.J.Al-Ani (Ph.D) FInstP | 28221