Numerical modeling of multi-junction solar cell-based CIGS with two sub-cells in parallel using silvaco TCAD

Abstract

The multi-Junction solar cell technique was suggested for achieving high efficiency. This paper describes the simulation of a solar cell for double junction CGS/CIGS solar cell using Silvaco ATLAS software. The simulated device performance was demonstrated in the form of current-voltage (I-V) characteristics and quantum efficiency (QE). By simulation of the tow solar cell, we have obtained for solar the top cell maximum opencircuit voltage 1.15V, a short circuit current density of 18.74 mA, a fill factor (FF) of 87.79 % and an efficiency of 18.27% and for the bottom solar cell is maximum opencircuit voltage 0.57 V, a short circuit current density of 21.52 mA, a fill factor (FF) of 82.82% and an efficiency of 10.26%. For the Tandem whose sub-cells are tied in parallel, the maximum open-circuit voltage 1.16V, a short circuit current density of 29 mA, a fill factor (FF) of 83.06% and an efficiency of 28.11%.

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“…This is because the increase in the width of the passivation region of the cell can increase the light absorption area of the cell and produce more photogenerated carriers, but the increase in width will also lead to an increase in the transverse transport distance of more photogenerated carriers (including the transverse transport distance of photogenerated carriers in the passivation region and the transverse transport distance of the insulating layer) and an increase in the chance of carrier recombination. At the beginning, the gain of increased photogenerated carriers due to the increase in the width of the passivation inlet area is greater than the loss due to the increase in the carrier transverse transport recombination caused by the increase in width, the carrier collected at the electrode increases, the short-circuit current density increases, with the increase in the width of the passivation inlet area, the gain due to the increase in the optical absorption area and the loss due to the carrier transverse transport recombination tend to balance, the short-circuit current density reaches the maximum, with the further increase of the width of the passivation inlet area, the gain brought by the increase of the light absorption area is not enough to offset the loss brought by the carrier transverse transport complex, and the short-circuit current density starts to decrease [19] . Figure 3 shows the transport characteristics of the substrate carriers at the emitter side.…”

“…In this paper, the HACL cell structure was constructed mainly using the ATLAS device simulator [19,20], and the effects of passivation region width, insulating layer width, emitter width, doping concentration in passivation and inlet regions, and substrate doping concentration on the performance of HACL cells were investigated.…”

Triple junction solar cell with Cu In1-x Gex Se as absorbents layers

“…The owing current might be considered as the sum of the short circuit current ISC, generated by the process of absorbing the photons. The current density is as follows [17][18][19]:…”

“…And this is not the only advantage of it. The band gap of CIGS can be varied from 1.011 to 1.67 eV in such a way by varying Ga composition to obtain the required band gap that meets the solar spectrum to absorb most of the photons [13,[16][17][18].…”

“…The triple junction solar cell was presented, it is composed of Zinc oxide as a window layer for all the sub-cells, cadmium sulfide (CdS) as an emitter layer for three sub-cells, copper gallium diselenide (CGS) as the first absorber layer, copper indium gallium diselenide (CIGS) as the second absorber layer, for the third absorber is copper indium diselenide and the substrate is molybdenum. Cu In1-xGaxSe2 is a compound with a band gap energy which is dependent on composition ratio x = Ga/(Ga + In) and can be extracted from the relation below [14,18]:…”