The Center for Materials Research

Picture of the Month - September 2023

MBE growth of cubic In_xGa_1-xN over the entire GaN/InN composition range

The increasing demand for efficient lighting sources and higher bandwidth communication mandates developing robust and reliable semiconductor materials suitable for large-scale industrial fabrication. Cubic In_xGa_1-xN are prime candidate materials for such optoelectronic applications. They promise to cover a vast range of emission wavelengths yet lack the internal piezoelectric fields native to the hexagonal nitrides. However, the large discrepancy in interatomic spacing and growth temperatures of GaN and InN hinder the heteroepitaxial growth of the intrinsically metastable c-In_xGa_1-xN over the whole composition range.

The perceived miscibility gap of c-GaN and c-InN is overcome by sophisticated strain management in the MBE growth of cubic c-In_xGa_1−xN films on c-GaN/AlN/3C-SiC/Si templates. Thorough characterization using HRXRD, Raman spectroscopy, and EDX confirms a singular, partially strained, cubic crystal phase. HR-STEM images reveal a modified CuPt-type ordering in c-In_xGa_1−xN when x ≈ 0.5, which is further supported by the FWHM of the emission line width. Low-temperature photoluminescence demonstrates the tunability of the emission energy from the near-ultraviolet to the near-infrared with a bowing coefficient of 2.4 eV.

Publication: Mario F. Zscherp, Silas A. Jentsch, Marius J. Müller, Vitalii Lider, Celina Becker, Limei Chen, Mario Littmann, Falco Meier, Andreas Beyer, Detlev M. Hofmann, Donat J. As, Peter J. Klar, Kerstin Volz, Sangam Chatterjee, Jörg Schörmann “Overcoming the Miscibility Gap of GaN/InN in MBE Growth of Cubic In_xGa_1−xN”, ACS Appl. Mater. Interfaces, 15, 33, 39513-39522 (2023). DOI: 10.1021/acsami.3c06319

This picture was submitted by Mario Zscherp, group of Prof. Dr. Sangam Chatterjee.

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