Optimizing the efficiency of InxGa1-xN/GaN quantum well solar cells using piezo-phototronic effects: The impact of external strain

Abstract

This work explores the efficiency enhancement of ${In}_x{Ga}_{1-x}N/GaN$ multiple quantum well (MQW) solar cells through the application of piezo-phototronic effect, which modifies piezoelectric polarization charges at interfaces to raise efficiency. We investigated the impact of external strain on the performance of these solar cells to address the problem of lattice mismatch and its effect on energy conversion efficiency. Using a numerical computational model, our approach involves examining the effects of external strain on the electrical, optical, and band structure properties of the cells. The results showed a notable improvement in energy conversion efficiency with increases of 29.35 % and 21.28 %, respectively, for indium compositions of 0.2 and 0.35. Additionally, the photocurrent density increased from 1.61 mA/cm² to 2.43 mA/cm² and from 4.44 mA/cm² to 5.83 mA/cm² for both compositions. Band energy realignment calculations clarify that this enhancement is due to the correction of piezoelectric charges caused by lattice mismatch strain. Our findings show that the piezo-phototronic effect can be used to optimize ${In}_x{Ga}_{1-x}N/GaN$ MQW solar cells, provide a viable means of increasing the use of solar energy and developing solar technology.