Polarization anisotropy and valence band ordering in semipolar (112¯2) AlInN/GaN heterostructures

authored by: Shawutijiang Sidikejiang, Philipp Henning, Uwe Rossow, Heiko Bremers, Ferdinand Scholz, Andreas Hangleiter
Abstract: Semipolar (112¯2) AlInN/GaN heterostructures on GaN templates were studied using photoluminescence (PL) spectroscopy both at 15 K and at room temperature. The polarization-resolved PL measurements revealed a dominant polarization along the [112¯3¯] c′ and a weaker signal along the [11¯00] m-direction, i.e., the two in-plane directions of the semipolar (112¯2) growth plane. We observed slightly different polarization degrees of 0.34±0.01, 0.25±0.02, and 0.20±0.01 at room temperature, respectively, depending on the degree of strain relaxation in the [11¯00] direction. From a theoretical model based on a k·p calculation, we find that the transition from the conduction band (CB) to the uppermost valence band (VB) is C for AlInN similar to AlN, followed by the transition A from the CB to the second VB, for a wide range of compositions. Thus, the in-plane transition matrix elements from the CB to the two topmost VBs near the Γ point of the Brillouin zone are dominated by M[112¯3¯] for the C transition and by M[11¯00] for the A transition. For the samples under consideration with an energy splitting of about 18±1meV, there is sizable thermal occupation of the second VB at room temperature, reasonably explaining the experimental results. The results show that AlInN possesses a band structure similar to AlN, which might explain the strong Stokes shift and the large variation in the band-gap values reported previously.
Type: Article
Journal: Physical Review B
Volume: 107
ISSN: 2469-9950
Publication date: 05.01.2023
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Electronic, Optical and Magnetic Materials, Condensed Matter Physics
Electronic version(s): https://doi.org/10.1103/physrevb.107.045202 (Access: Closed)
https://link.aps.org/doi/10.1103/PhysRevB.107.045202 (Access: Unknown)

BibTeX

@article{80e7221b3fc144d2a137ca169a8b7bb3,
title = "Polarization anisotropy and valence band ordering in semipolar (112¯2) AlInN/GaN heterostructures",
abstract = "Semipolar (112¯2) AlInN/GaN heterostructures on GaN templates were studied using photoluminescence (PL) spectroscopy both at 15 K and at room temperature. The polarization-resolved PL measurements revealed a dominant polarization along the [112¯3¯] c′ and a weaker signal along the [11¯00] m-direction, i.e., the two in-plane directions of the semipolar (112¯2) growth plane. We observed slightly different polarization degrees of 0.34±0.01, 0.25±0.02, and 0.20±0.01 at room temperature, respectively, depending on the degree of strain relaxation in the [11¯00] direction. From a theoretical model based on a k·p calculation, we find that the transition from the conduction band (CB) to the uppermost valence band (VB) is C for AlInN similar to AlN, followed by the transition A from the CB to the second VB, for a wide range of compositions. Thus, the in-plane transition matrix elements from the CB to the two topmost VBs near the Γ point of the Brillouin zone are dominated by M[112¯3¯] for the C transition and by M[11¯00] for the A transition. For the samples under consideration with an energy splitting of about 18±1meV, there is sizable thermal occupation of the second VB at room temperature, reasonably explaining the experimental results. The results show that AlInN possesses a band structure similar to AlN, which might explain the strong Stokes shift and the large variation in the band-gap values reported previously.",
author = "Shawutijiang Sidikejiang and Philipp Henning and Uwe Rossow and Heiko Bremers and Ferdinand Scholz and Andreas Hangleiter",
note = "Publisher Copyright: {\textcopyright} 2023 American Physical Society.",
year = "2023",
month = jan,
day = "5",
doi = "10.1103/physrevb.107.045202",
language = "English",
volume = "107",
journal = "Physical Review B",
issn = "2469-9950",
publisher = "American Institute of Physics",
number = "4",
}