Highly efficient ARC less InGaP/GaAs DJ solar cell numerical modeling using optimized InAlGaP BSF layers

Abstract

An effective BSF is a key structural element for an efficient solar cell, either in a multi-junction or in a single-junction device. In this paper, two important materials AlGaAs and InAlGaP with their varied thickness (i.e. 0.05-1.0) μm both for top BSF and bottom BSF cells are investigated using the computational numerical modeling TCAD tool Silvaco ATLAS. It has been found that under the current matching condition with the relatively thinner (30 nm) top BSF layer and the thicker (1,000 nm) bottom BSF layer, the cell exhibit an overall enhancement of short-circuit current density J sc and open circuit voltage Voc thereby improving the overall efficiency of the cell. A wide band gap material In 0.5 (Al 0.7 Ga 0.3 ) 0.5 P is proved to be a better choice for both window and BSF layer by increasing 6.2% more efficiency than using other widely used Al 0.7 Ga 0.3 As material under the same cell configuration because of its high photo generation rate. For this optimized cell structure, the maximum J sc = 16.10 mA/cm 2 , V oc = 2.392 V, and fill factor = 87.52% are obtained under AM1.5G illumination, exhibiting a maximum conversion efficiency of 32.1964% (1 sun) and 36.6781% (1,000 suns). This work reports the Influence of different BSF material and structures on the characteristics and efficiency of Multi-Junction solar cells. The detail photo-generation rates and EQE in this optimized ARC less DJ solar cell structure are also observed. The major stages of the modeling are explained and the simulation results are validated with published experimental data to demonstrate the accuracy of our results produced by the model utilizing this technique.

Introducing a novel high-efficiency arc less heterounction DJ solar cell

“…Charge carriers produced by irradiation of photons are separated at the p-n junction and back surface field (BSF) layer, which reduces surface recombination of charge carriers by producing an electric field. The tunnel junction provides conditions for passage of the charge carriers from a route having low resistance by creating a low-width discharge area [4][5][6][7][8]. Figure 1 shows a dual-junction solar cell.…”

“…where G is photo-generation rate, 0 is the internal quantum efficiency, P is the cumulative effect of reflections, transmissions and losses due, ʎ is the wavelength, h is the Plank's constant, c is the light speed, α is the absorption coefficient for each set of (n,k) and y is the relative distance [4]. Figures 11 and 12 show that photogeneration decreased from the top of the cell to the bottom due to the reduced absorption of photons in the lower layers.…”

“…The efficiency of this cell was 25.14% under radiation of AM1.5 (1 sun) [3]. Singh et al obtained efficiency of 32.196% under radiation of AM1.5 (1 sun) by inserting In 0.5 (Al 0.7 Ga 0.3 ) 0.5 P into the back surface field (BSF) layer at the bottom of a InGaP/GaAs dual-junction cell [4]. Nayak et al reported a efficiency of 39.15% under radiation of AM1.5 (1000 sun) by creating an extra electric field using two back surface field (BSF) layers [5].…”

The Design and Optimization of GaAs Single Solar Cells Using the Genetic Algorithm and Silvaco ATLAS

“…ATLAS solves Poisson's equation; carrier continuity equations for both electrons and holes were solved, the driftdiffusion transport model. Refractive index of each material and important parameters for the simulation of solar cells are obtained from [9,10,12] and from the Sopra database incorporated in Silvaco. Different physics models were used to calculate recombination and carrier mobility for a solar cell structure.…”

“…Recently, the single solar cells performance made a significant growth, an efficiency of 27% was recorded for the GaAs single cells [8]. A detailed set of simulated material parameters used in our design has been taken from previous publication [9][10][11]. The purpose of this work is to design a single solar cell based on GaAs that is highly efficient and to investigate its performance.…”