The First International Palestinian Conference on Nanotechnology for Advanced Material and Devices

A new type of solar cells which are designed from single crystals using silver and gold metals to construct point contacted photocells are reported and discussed. The influence of the driving electric field on the performance of the device was tested. The current density-electric field dependence curve reflected a space charge limited photocurrent effect being dominant in the filed region of 1-4.3 V/cm. In addition, the solar cell short circuit and loaded current dependence on the excitation intensity was measured. The short circuit current is observed to exhibit exponential trap distribution effect and supralinear recombination at low and high illumination intensities, respectively. The device displays a current density of 0.5 (mA/cm2) for excitation intensity of 76 klux. When loaded it displayed a stable power dissipation curve. Such behavior reflects the novelty of these types of cells for future application. PACS: 71.55.Ht, 72.20.Dp, 72.20.Jv, 72.40.+w, 72.80.Jc, 78.20.Ci

The effects of Co doping on structural properties of Bi1.5Zn0.92 Nb1.5O6.92 (BZN) Pyrochlore ceramics have been investigated. Co atoms were substituted into pure samples in accordance to three types of composition, Bi1.5Zn0.92Nb1.5-xCoxO6.92- x for, Bi1.5Zn0.92Nb1.5-xCoxO6.92-x + Bi1.5Zn0.92Nb1.5-3x/5CoxO6.92 and Bi1.5Zn0.92Nb1.5-xCoxO6.92-x +(Bi1.5Zn0.46)(Zn0.46-3x/6Nb1.5-3x/5Cox)O6.92- x/2 for substitution of. The structural analysis of Bi1.5 Zn0.92Nb1.5-xCoxO6.92-x revealed that the single phase of pyrochlore can be obtained for x =0.03 and 0.04 only. Further increasing of Co content caused a second phase of ZnO appearance and its amount increased as doping increase. Co doping affects the lattice constant and degree of texturization but has no effects on the BZN grain size. The grain size of the single phase pyrochlore was found to be doping independent and of the order of 66 nm. To understand the dramatically changes associated with the appearance of ZnO, detailed structural analysis were handled. The ZnO hexagonal phase grows systematically on the BZN creating grains that exceed in size that of the pyrochlore at high x ratios.
PACS : 72.80.Tm, 77.22.Gm, 78.20.Bh,
Keywords: Pyrochlore; Structure and Microstructure; Doping; Grain