Indium‐rich InGaN/GaN solar cells with improved performance due to plasmonic and dielectric nanogratings

• Published in: Energy science & engineering 2019-12, Vol.7 (6), p.2469-2482
• Main Authors: Kumawat, Uttam K., Kumar, Kamal, Bhardwaj, Priyanka, Dhawan, Anuj
• Format: Article
• Language: English
• Subjects: Absorption; Alloys; broadband absorption; Efficiency; Electromagnetic absorption; Energy conversion efficiency; FDTD simulations; Gallium; Gallium nitrides; Indium; Indium gallium nitrides; InGaN solar cells; Light; light trapping; nanogratings; Nanoparticles; Nanowires; Photonics; Photovoltaic cells; Quality; Researchers; Solar cells; Solar power; surface plasmons; Wavelengths
• ISSN: 2050-0505; 2050-0505
• DOI: 10.1002/ese3.436

In this study, we propose an indium‐rich InGaN/GaN p‐i‐n thin‐film solar cell which incorporates a dual nanograting (NG) structure: Ag nanogratings (Ag‐NGs) on the backside of the solar cell and gallium nitride nanogratings (GaN‐NGs) on the frontside. Finite‐difference time‐domain (FDTD) simulation results show that the dual NG structure couples the incident sunlight to the plasmonic and photonic modes, thereby increasing the absorption of the solar cell in a broad spectral range. It is observed that the solar cells having the dual nanograting structures have a significant enhancement in light absorption as compared to cells having either no nanogratings or having only the frontside nanogratings or only the backside nanogratings. Analysis of light absorption in solar cells containing the dual NG structures showed that the absorption enhancement of longer wavelengths is mostly due to the Ag‐NGs on the backside and of shorter wavelengths is mostly due to the GaN‐NGs on frontside of the solar cell. The Jsc and power conversion efficiency (PCE) are calculated under AM1.5G solar illumination and are observed to be significantly enhanced due to the presence of optimized dual NG structures. While there is an increase in Jsc from 17.88 to 23.19 mA/cm2 (~30% enhancement), there is an increase in PCE from 15.49% to 20.24% (~31% enhancement) under unpolarized light (average of TM and TE). Moreover, the study of oblique light incidence shows significantly larger Jsc of the dual nanograting solar cells compared to the cells with no nanogratings. An Indium‐rich InGaN/GaN p‐i‐n thin film solar cell which incorporates a dual nanograting (NG) structure—Ag‐NGs on the back side and GaN‐NGs on the front side of the solar cell—have been investigated by performing FDTD simulations. It is observed that solar cells having the dual nanograting structures have a significant enhancement in light absorption and Jsc as compared to cells having either no nanogratings or having only the front side nanogratings or only the back side nanogratings.