CNT based enhanced GaAs/InAs Multiple quantum well (MQW) solar cell

Abstract

This work presents the optimized model and results of numerical simulations and analysis of CNT based GaAs/InAs multiple quantum wells (from 5 to 70 QWs) GaAs solar cell. These QWs is found to extend the absorption edge beyond that of the GaAs bandgap. Further, with the introduction of the wide bandgap InGaP back surface field (BSF) layer in the model, efficiency is enhanced due to the reflection of unabsorbed photons from the bottom of the device back into the quantum well. The proposed model uses a heterogeneous CNT layer as top semi-transparent electrode. It is observed that this CNT top layer with lower sheet resistance and better light transmission can significantly improve the overall efficiency. Our optimized cell with 35 number 25nm quantum well structure with 100 nm CNT top layer with sheet resistance of 128 Ω/□ is found to increase the efficiency up to 34.12% (with CNT top layer) from 32.46%(without CNT top layer). EQE of the cell is nearly 90%. To show the accuracy of our findings, the key phases of the numerical modelling are presented, and the base simulation data are checked using standard experimental data. An essential step towards creating commercially viable QWSCs is the effective application of the suggested CNT-based QWSC model within a modern TCAD tool environment (Silvaco ATLAS).