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The objective of this work is to simulate and optimize the physical properties of the quaternary semiconductor InGaAsP deposited on InP substrate, in order to enhance the efficiency of photovoltaic cells through the optimization of the bandgap and the absorption coefficient. To this end, the impact of the Gallium and Phosphorus concentrations on the strain as well as on the bandgap energy were studied. We have found that the absorption coefficient increases with the strain to reach 4.4 × 104 cm−1, thus, the strain allows to provide additional flexibility on the structure of solar cells and makes the alloy InGaAsP/InP promising for the design of photovoltaic cells based on the quaternary InGaAsP compound. [ABSTRACT FROM AUTHOR]

In this work, theoretical investigation of the InGaN multi-junction solar cells is carried out. Calculations were performed under 1-sun AM1.5 using the one diode ideal model and respecting rigorously the current matching condition. Tandem cells comprising two, three and four junctions were simulated. Optimum compositions of the sub-cells have been identified and conversion efficiencies of 25.9, 34.7, 39.7 and 42.2 % for one, two, three and four junctions, respectively are obtained. [ABSTRACT FROM AUTHOR]

A theoretical investigation of the sensitivity of an optical liquid sensor, based on photonic crystal waveguide, is carried out. The sensing principle is based on the variation of the effective index of the waveguide induced by analyte refractive index change. The sensor modelling is carried out by using the 3D finite element method. The influence of geometrical parameters on the sensor sensitivity has been investigated. The results show that the sensitivity can be optimized by an appropriate choice of the geometrical parameters and a sensitivity superior to 20 has been achieved, near the cut-off in the slow light region, which is several times higher than that can be achieved with conventional waveguides. [ABSTRACT FROM AUTHOR]

A theoretical investigation of an optical liquid sensor, based on asymmetric directional coupler employing slot optical waveguides, is carried out. The sensing principle is based on the shift in the waveguide transmitted spectrum induced by analyte refractive index change. Silicon-on-insulator technology has been assumed in sensor design, and sensor modelling is carried out by using the coupled modes theory and the finite element method. The influence of geometrical parameters on the sensor characteristics has been investigated. A minimum detectable refractive index change of the order of 10 can be theoretically predicted. [ABSTRACT FROM AUTHOR]