Manivannan P. V.

The aim of the present work is to study the effect of process induced defects on the transport mechanism in ITO/InP solar cells. A detailed analyses of electrical properties along with XPS studies have been carried out on ITO/p-InP cells prepared by reactive electron beam evaporation and spray pyrolysis techniques. It is observed that thermionic field emission (TFE) in ITO/p-InP junctions prepared by e beam and tunnelling (below 300 K) and recombination at depletion region (above 300 K) in sprayed junctions are the dominant transport mechanisms. The cells prepared by both the techniques conform to Semiconductor-Insulator-Semiconductor model and the interfacial layer comprises of In2O3 and InPO4 as revealed by XPS data.

The electrical properties of Indium tin oxide(ITO)/p-indium phosphide (InP) junctions prepared at different temperatures by reactive electron beam evaporation technique have been studied. A maximum of 10.0% photo conversion efficiency under 100 mW cm-2 illumination (without front metal grid and antireflection coating) has been observed. Analyses of the results indicate an interfacial oxide layer consisting of indium oxide and indium orthophosphate and the ITO/p-InP junction correspond to the semiconductor-insulator- semiconductor SIS model. An attempt has been made to understand the nature of the interfacial layer.

Indium tin oxide (ITO)/p-indium phosphide (InP) junctions have been prepared by the spray pyrolysis technique and the photovoltaic properties have been reported earlier. Continuing our efforts to understand the transport mechanism across these junctions, XPS, current-voltage (dark), and capacitance-voltage measurements have been carried out on the samples having 10.2% photovoltaic efficiency under 100 mW/cm2 illumination. The XPS studies have confirmed an interfacial layer consisting of In2O 3 and InPO4. The transport mechanism above 300 K is found to be dominated by recombination at the depletion region. The MIS model proposed in our earlier paper to account for the photovoltaic and transport properties is confirmed for sprayed ITO/p-InP junctions in the present study. © 1995 American Institute of Physics.

The contribution of effective mass to the theoretical calculations for resistivity as a function of carrier density in indium tin oxide films is clarified. © 1994 IOP Publishing Ltd.

Highly conducting (ρ = 2.5 × 10-4 Ω cm) and transparent (92%) tin-doped indium oxide (ITO) films have been prepared by a reactive electron beam evaporation technique; the dependence of these properties on the substrate temperature (150-275 °C) and tin doping (0-15% by weight) has been studied. Hall mobility in the films has been found to increase with substrate temperature and decrease with the addition of tin. An attempt has been made to distinguish the different scattering mechanisms responsible for electrical conduction; it is found that the grain boundary scattering is negligibly small in these films. An analysis of the optical data has been made to evaluate the broadening parameter and the Burstein-Moss shift in optical band gaps.

Conventional two-stroke spark-ignition (SI) engines have difficulty meeting the ignition requirements of lean fuel-air mixtures and high compression ratios, due to their breaker-operated, magneto-coil ignition systems. In the present work, a breakerless, high-energy electronic ignition system was developed and tested with and without a platinum-tipped-electrode spark plug. The high-energy ignition system showed an improved lean-burn capability at high compression ratios relative to the conventional ignition system. At a high compression ratio of 9:1 with lean fuel-air mixtures, the maximum percentage improvement in the brake thermal efficiency was about 16.5% at 2.7 kW and 3000 rpm. Cylinder peak pressures were higher, ignition delay was lower, and combustion duration was shorter at both normal and high compression ratios. Combustion stability as measured by the coefficient of variation in peak cylinder pressure was also considerably improved with the high-energy ignition system. © Copyright 1995 Society of Automotive Engineers, Inc.