Modeling of Temperature Dependence of Λ-graded InGaN Solar Cells for Both Strained and Relaxed Features

Authors

Mirsaeid Sarollahi, University of Arkansas, FayettevilleFollow
Mohammad Zamani-Alavijeh, University of Arkansas, FayettevilleFollow
Manal Abdullah Aldawsari, University of Arkansas, FayettevilleFollow
Rohith Allaparthi, University of Arkansas, FayettevilleFollow
Md Helal Uddin Maruf, University of Arkansas, Fayetteville
Malak Refaei, University of Arkansas, FayettevilleFollow
Reem E. Alhelais, University of Arkansas, FayettevilleFollow
Yuriy I. Mazur, University of Arkansas, FayettevilleFollow
Morgan E. Ware, University of Arkansas, FayettevilleFollow

Document Type

Article

Publication Date

10-2022

Keywords

solar cell; InGaN alloy; polarization doping; graded structure; strain; relax

Abstract

The temperature dependence of Λ-graded InGaN solar cells is studied through simulation using nextnano software. Λ-Graded structures have been designed by increasing and then decreasing the indium composition in epitaxial InGaN layers. Due to polarization doping, layers of p-type and n-type doping arise without the need for impurity doping. Different individual structures are designed by varying the indium alloy profile from GaN to maximum indium concentrations, x_max , ranging from 20% to 90% pseudomorphically strained to a GaN substrate and from 20% to 100% for completely strain-relaxed materials and linearly decreases back to GaN. For In_xGa_1-xN with x >similar to 0.9, if the material is strained to the GaN lattice constant, it is predicted to have a negative band gap. So this case is not considered here. The temperature dependence of the electrical and optical properties as they relate to the solar efficiency of the Λ-graded structures under relaxed and strained conditions are studied. Additionally, the dimensionless absorption coefficients are fitted and plotted as functions of the band gap under both strained and relaxed conditions at different temperatures. As a result, the generation rates as functions of the penetration depth within a cell can be calculated in order to obtain the solar cell parameters including efficiency for each Λ-graded structure at different temperatures. Under the strained condition, the x_max , where the solar cell efficiency reaches its maximum for each temperature, decreases as the temperature increases. At the same time, under the relaxed condition, at low temperatures (T = 100-400 K), x_max is 100 % , that is, grading to InN results in maximum efficiency, while at higher temperatures (T = 500-800 K), x_max decreases with the increasing temperature.

Citation

Sarollahi, M., Zamani-Alavijeh, M., Aldawsari, M. A., Allaparthi, R., Maruf, M. U., Refaei, M., Alhelais, R. E., Mazur, Y. I., & Ware, M. E. (2022). Modeling of Temperature Dependence of Λ-graded InGaN Solar Cells for Both Strained and Relaxed Features. Frontiers in Materials, 9, 1006071. https://doi.org/10.3389/fmats.2022.1006071

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This work is licensed under a Creative Commons Attribution 4.0 International License.