Open AccessLattice-matched III-nitride structures comprising BAlN, BGaN, and AlGaN for ultraviolet applications
Author(s) -
Feras AlQatari,
Muhammad Sajjad,
Ronghui Lin,
KuangHui Li,
Udo Schwingenschlögl,
Xiaohang Li
Publication year - 2021
Publication title -
materials research express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.383
H-Index - 35
ISSN - 2053-1591
DOI - 10.1088/2053-1591/ac1caa
Subject(s) - ultraviolet , materials science , heterojunction , optoelectronics , wavelength , refractive index , lattice constant , nitride , lattice (music) , laser , band gap , ternary operation , optics , nanotechnology , physics , diffraction , layer (electronics) , computer science , acoustics , programming language
The optical properties of BAlN, BGaN and AlGaN ternary alloys are investigated using hybrid density functional for the design of lattice-matched optical structures in the ultraviolet spectrum. The calculated AlGaN properties agree well with previous reports, validating the model. A peculiar non-monotonic behavior of the refractive index as a function of the boron composition is found. The results of this calculation are interpolated to generate a three-dimensional dataset, which can be employed for designing a countless number of lattice-matched and –mismatched heterostructures. These heterostructures could span a range of operating wavelengths well into the deep ultraviolet with refractive indices ranging from 1.98 to 2.41 for AlN at 0 eV and GaN near the GaN bandgap, respectively. An example is shown where a lattice-matched heterostructure, AlN/B 0.108 Ga 0.892 N, is applied for DBR applications with a large index difference. A DBR comprising the AlN/B 0.108 Ga 0.892 N heterostructure at the UV wavelength of 375 nm is found to exceed 93% peak reflectivity with only 10 pairs and reaches 100% reflectivity with 35 pairs. For a chosen design with 25 pairs, the DBR has a peak reflectivity of 99.8% and a bandwidth of 26 nm fulfilling the requirements of most devices especially ultraviolet vertical-cavity surface emitting lasers.