Abstract 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). Manuscript profile

Abstract The tunability of the InGaN band gap energy over a wide range provides a noble spectral match to sunlight, making it a suitable material for photovoltaic solar cells. The ineffectiveness of single junction solar cell to convert solar full spectrum into electrical energy leads to transparency loss in addition with excess excitation loss. An efficient BSF layer is an essential structural element to attain high efficiency in solar cells. In this work the impact of the BSF layer for InGaN single-junction and multi-junction solar cells is studied using the computational numerical modeling with Silvaco ATLAS simulation technique. The open circuit voltage (Voc) and circuit current density (Jsc) characteristics of the simulated cells and the variation of external quantum efficiency as a function of solar cell structures have been studied. For the optimized cell structure, the maximum Jsc = 14.6 mA/cm², Voc = 3.087 V, and fill factor (FF) = 88.15% are obtained under AM1.5G illumination, exhibiting a maximum conversion efficiency of 36.1%. Manuscript profile