Bandgap engineered 1.48 eV GaAs_0.95P_0.05 solar cell with enhanced efficiency using double BSF layer

Abstract

One of the most important criteria to design more than 30% efficient III–V compound/Si based dual junction solar cell is that we must design atleast 20% efficient III–V compound material top cell. In this regard, we designed a bandgap engineered GaAs0.95P0.05 single junction solar cell with reduced bandgap of (E g ) = 1.48 eV. Reducing the bandgap from 1.72 eV to 1.48 eV for GaAs0.95P0.05 cell leads to generate higher short circuit current, while having the tradeoff with the open circuit voltage. Due to small change in lattice constant of GaAs0.95P0.05 cell, some recombination is observed near the junction area. Although the minimal degradation is observed in open circuit voltage, the higher short circuit current drives the overall efficiency of the GaAs0.95P0.05 single junction solar cell. The designed solar cell provides an extended internal absorption for longer wavelength of spectrum. The high electron mobility of 8500 cm2 V–S−1 was observed with very high electron to hole mobility ratio of 21.25. The optimization of the cell is done using two back surface field layers (AlInP and AlGaInP) of higher bandgap material. The high short circuit current density of J SC = 25.93 mA cm−2 with V OC = 1.1635 V achieved by the designed cell with the highest efficiency of η = 25%. The solar cell is irradiated under 1-Sun solar irradiation in the AM1.5 G environment providing 1000 W m−2 of power spectral density. The External and Internal Quantum efficiency of more than 95% is achieved by the designed solar cell.

GaAs0.95P0.05 single junction solar cell with InP QW in p-i-n region for sub-bandgap photon absorption

“…Also, the open circuit voltage ranges from 1.157 V to 1.21 V with the FF range of 77.85% to 81.70% [9,19,20,30]. Our previously reported model achieved η = 24.59%, with J sc = 25.90 mA cm −2 , FF = 81,84% and V oc = 1.18 V [7]. The proposed model with QWs in the p-i-n region enhances the current density to Jsc = 33.948 mA cm −2 and Fill factor to FF = 84.89%.…”

“…The single junction solar cell based on compound and perovskite materials have shown little higher than 20% efficiency [4][5][6]. Recently, we developed the model of GaAsP cell having more than 20% efficiency [7], which is higher than the GaInP based single junction solar cell efficiency [8]. The GaAsP Cells are also grown on GaP/Si template using direct monolithic process and molecular beam epitaxy, which are having below 20% efficiency [9][10][11], and also with the GaAs bulk substrate [12].…”