We report the effect of Si, Cr, Sc doping in the crystalline structure, optical and discharge characteristics of MgO
thin films. Silicon and multiple (Si, Cr, Sc) doped MgO thin films demonstrate higher secondary electron emission
(SEE). Si doping with Cr and Sc doping in MgO films shows much higher SEE as compared to pure and only Si doped
MgO films. The importance of optimum amount of Sc doping is seen in our study where SEE reduced with further
increase in Sc doping. The structural attributes of MgO films are correlated to the observed changes in discharge
characteristics in the context of varying amount of Si, Sc, and Cr doping.
Use of selective emitters is an important step in increasing the efficiency of commercial crystalline Si solar cells, but
costs must be kept under control. Laser doping allows selective doping of precisely defined regions without the need for
process- and labor-intensive photolithography steps while maintaining or improving cell quality. Laser processing
parameters must be investigated to optimize doping and minimize defect generation and contact resistance to realize
optimal photovoltaic performance. Lasers are available in a wide range of wavelengths, pulse durations, fluences, and
energy distributions. Processing parameters must be selected with both performance and industrial feasibility in mind.
Printing technology is a low cost technique for the processing of organic electronic devices. Here, we report printing characteristics of poly (3,4-ethylenedioxythiophene) : poly (styrenesulfonate) (PEDOT:PSS), typically used as hole injection/transport layer in various organic devices e.g. organic light emitting diodes, solar cells, and field effect transistors. In this work, we optimize drop spacing and substrate temperature during ink-jet printing of PEDOT:PSS films on rigid (glass) and flexible (PET) substrates. Morphological characterization of the films was performed using optical and scanning electron microscopy. Optical transmittance was measured using UV-Vis spectrophotometer and sheet resistance of the films was measured using four-point probe technique. We find that substrate temperature and drop spacing significantly affect the morphology, in our case decreasing these lead to smooth morphology of the ink-jet printed PEDOT-PSS films.
We report that the vacuum annealing of MgO films at 225°C results in the removal of water based contamination and
the secondary electron emission coefficient increases from 0.09 to 0.15. The effective secondary electron emission yield
increases from 0.2 to 0.75 at 200 mbar chamber pressure, as temperature increases to 250 °C. The effective secondary
electron emission yield at 200, 350 and 800 mbar pressure shows similar trend during the heating as well as cooling of
the MgO sample. Thermionic emission, smaller surface band bending and the removal of impurities at high temperature
are possible reasons for the increase in secondary electrons of MgO thin films.
In this work, a new subscriber access network architecture has been proposed. It uses optical add-drop multiplexer and wavelength division multiplexing. In order to alleviate the limitation on supportable number of users use of OAS has been investigated. It is found that with all the degradation in OAs, the number o users for a typical network is limited to 384.
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