III-Nitride NanoWire array Solar Cells (NWSCs) combine the inherent properties of III-N semiconductors with waveguiding and confinement properties of nanowire arrays. In the present paper, some design guidelines of NWSCs made from Indium-Gallium-Nitride InGaN alloys are presented. Firstly, a detailed balance analysis was performed to show the importance of using InGaN materials to effectively convert the light to electricity, followed by an optical modelling to point out the advantages of using periodic nanowire arrays in designing solar cells. From the detailed balance analysis, it is expected that single junction solar cells made from In0. 63Ga0. 37N alloy result in the highest light-to-electricity conversion efficiency of 31%, and the Rigorous Coupled Wave Analysis RCWA simulations show that nanowire arrays made from InxGa1-xN fractions (x values) ranging between 50 and 77% alloys may achieve efficiencies of more than 33%, with a maximum efficiency of 37. 7% for In0. 67Ga0. 33N NW array. Substrate choice, array density and filling material impacts on device performance were also studied.

To enhance lasers’ power and improve their performance, a model was applied for the waveguide design of 400 nm InGaN/InGaN semiconductor laser, which is much easier to implement. The conventional and new laser structures were theoretically investigated using simulation software PICS3D, which self-consistently combines 3D simulation of carrier transport, self-heating, and optical waveguiding. Excellent agreement between simulation and experimental results was obtained by careful adjustment of the material parameter in the physical model. Numerical simulation results demonstrate that the new waveguide structure can efficiently increase the output power, lower the threshold current, and improve the slope efficiency, which is simply applicable to any kind of InGaN edge emitting lasers. Flatten band gap in the p-side of the InGaN laser diode in new laser structure resulted in an increase in the hole current density in the quantum well while simultaneously the electron confinement in the active region was effectively created, leading to the increased stimulated recombination rate. Furthermore, optical mode-overlap with heavily p-doped was declined, which is the main reason for a better performance of InGaN laser diode.

An efficient double junction InGaN/CIGS solar cell can be simulated using Silvaco ATLAS software. In this study, a thin CdS top cover layer is used as the anti-reflector layer. To reach the current matching condition, changing the thickness of this CdS layer, we can enhance the short-circuit currents of both the top and bottom cells. To gain a desired efficiency, different design parameters, such as the doping concentrations and the thicknesses of the various layers of the cell are optimized. This cell is designed to be used in a real environmental situation. Considering the proposed structure and the simulation results, an optimum efficiency of 41. 87% is achieved and also the obtained fill factor is equal to 75. 16%.

A solar cell is an electronic device which not only harvests photovoltaic effect but also transforms light energy into electricity. In photovoltaic phenomenon, a P-N junction is created to form an empty region. The presented paper aims at proposing a new highly efficient InGaN/Si double-junction solar cell structure. This cell is designed to be used in a real environmental situation, so only structural parameters are optimized. In the present structure, a thin layer of Cd-S is used as the anti-reflector window layer. The cell is simulated using ATLAS-SILVACO software and its maximum efficiency is computed to be 37. 23%. Considering the supposed structure, the findings show that the efficiency of this solar cell, which is 37. 32%, is so far the highest reported efficiency amongst all solar cells.

This paper presents a model of a photovoltaic (PV) cell based on InGaN instead of regular cells made up of silicon, while polarization effects are considered. The model is constructed under Matlab/Simulink environment upon the equivalent electrical circuit of the PV cell. The way components of the equivalent electrical circuit are connected leads to establishing mathematical equations, thus, describing the behavior of the PV cell under different environmental and physical conditions. Once the PV cell model is validated by means of experimental results, it has been extended to build a model of a PV module made up of numerous cells interconnected in diverse potential configurations depending on the expected outputs in terms of current/voltage. The model has shown promising and accurate results and would aid researchers in the field of power electronics to consider it as a truthful PV generator (PVG).

The performance characteristics of InGaN double-quantum-well (DQW) laser diodes (LDs) with different last barrier structures are analyzed numerically by Integrated System Engineering Technical Computer Aided Design (ISE TCAD) software. Three different kind of structures for last quantum barrier including doped-GaN, doped-AlGaN and GaN/AlGaN superlattice last barrier are used and compared with conventional GaN last barrier in InGaN-based laser diodes. Replacing the conventional GaN last barrier with p-AlGaN increased hole flowing in the active region and consequently the radiative recombination which results in the enhancement of output power. However it caused increasing the threshold current due electron overflowing. For solving this problem, the last barrier structure altered with GaN/AlGaN superlattice. The simulation indicates that the electrical and optical characteristics of LDs with the superlattice last barrier, like output power, differential quantum efficiency (DQE) and slope efficiency, has significantly improved, besides the threshold current decreased. The enhancement is mainly attributed to the improvement of hole injection and the blocking electron overflowing which are caused by the reduction of polarization charges at the interface between the barrier and well, and electron blocking layer (EBL).

In this paper, a numerical model is used to analyze an optical absorption coefficient according to the electronic properties of InGaN/GaN multiple-quantum-well solar cells (MQWSC) under hydrostatic pressure. Finite difference techniques have been used to acquire energy eigenvalues and their corresponding eigenfunctions of InGaN/GaN MQWSC and the hole eigenstates are calculated via a 6 6 k. p method under the applied hydrostatic pressure. All symmetry-allowed transitions up to the fifth subband of the quantum wells (multi-subband model) and barrier optical absorption, as well as the linewidth due to the carrier-carrier and carrier-longitudinal optical (LO) phonon scattering, are considered here. A change in the pressure up to 10 GPa increases the intraband scattering time up to 38fs and 40fs for light and heavy holes, respectively, raises the height of the Lorentz function and reduces the excitonic binding energy. The multi-subband model has a positive effect on the optical absorption coefficient and increases it by %17, contrary to the pressure function.