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New article by grad student Daniel Wines and Dr. Ataca

October 7, 2020 11:40 AM
“Engineering the Electronic, Thermoelectric, and Excitonic Properties of Two-Dimensional Group-III Nitrides through Alloying for Optoelectronic Devices (B1–xAlxN, Al1–xGaxN, and Ga1–xInxN)”

Daniel Wines, Fatih Ersan, Can Ataca

STEAM Lab members Daniel Wines, Fatih Ersan (former) and Dr. Ataca discover new phases of two-dimensional group-III nitride alloys. By calculating the electronic, optical and thermoelectric properties, they demonstrate that these newly discovered materials can be suitable for future optoelectronic and thermoelectric devices.

ACS Appl. Mater. Interfaces 2020, https://doi.org/10.1021/acsami.0c11124

URL: https://pubs.acs.org/doi/abs/10.1021/acsami.0c11124

Abstract: Recently, two-dimensional (2D) group-III nitride semiconductors such as h-BN, h-AlN, h-GaN, and h-InN have attracted attention because of their exceptional electronic, optical, and thermoelectric properties. It has also been demonstrated, theoretically and experimentally, that properties of 2D materials can be controlled by alloying. In this study, we performed density functional theory (DFT) calculations to investigate 2D B1–xAlxN, Al1–xGaxN, and Ga1–xInxN alloyed structures. We also calculated the thermoelectric properties of these structures using Boltzmann transport theory based on DFT and the optical properties using the GW method and the Bethe–Salpeter equation. We find that by changing the alloying concentration, the band gap and exciton binding energies of each structure can be tuned accordingly, and for certain concentrations, a high thermoelectric performance is reported with strong dependence on the effective mass of the given alloyed monolayer. In addition, the contribution of each e–h pair is explained by investigating the e–h coupling strength projected on the electronic band structure, and we find that the exciton binding energy decreases with increase in sequential alloying concentration. With the ability to control such properties by alloying 2D group-III nitrides, we believe that this work will play a crucial role for experimentalists and manufacturers focusing on next-generation electronic, optoelectronic, and thermoelectric devices.