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The paper deals with the conception and feasibility of the device structure based on the optimized PIN-(In, Ga)N homojunction solar cells. A new and efficient model combining the most realistic ones considering the impacts of band gap narrowing, collection efficiency, Shockley-Read-Hall recombination, and interface polarization is proposed to examine the solar cells' performance numerically. The functioning processes of n-In0.42Ga0.58N/i-(In, Ga)N/p-In0.42Ga0.58N solar cells at room temperature were investigated by calculating their characteristics for the AM1.5D, AM1.5G, and AM0 American Society for Testing and Materials experimental data. Our results show that the indium content, thickness, and defect density of the intrinsic layer strongly influence the characteristics of the InGaN solar cells. As the In-mole fraction increases, Voc, FF and efficiency diminish to reach an independent regime for high In-content. A higher-quality 2μm−In0.43Ga0.57N for 1014cm−3 defect concentration can exhibit as high an efficiency as ≅11.3%, dropping to ≅4.12% for 1016cm−3 one.

By means of a combination of Quantum Genetic Algorithm and Hartree-Fock-Roothaan method, the changes in linear, third-order nonlinear and total refractive index associated with intra-conduction band transition are investigated with and without shallow-donor impurity in wurtzite (In,Ga)N-GaN spherical quantum dot. For both cases with and without impurity, the calculation is performed within the framework of single band effective-mass and parabolic band approximations. Impurity's position and relaxation time effects are investigated. It is found that the modulation of the refractive index changes, suitable for good performance optical modulators and various infra-red optical device applications can be easily obtained by tailoring the relaxation time and the position of the impurity. [ABSTRACT FROM AUTHOR]