MBE growth, structural, optical, and thermal properties of AlBN
Abstract
We report plasma-assisted molecular beam epitaxial growth of AlBN thin films on a nitrided c-plane Al2O3 substrate. The AlBN film epitaxially grows in rotational alignment with an out-of-plane/in-plane directions of AlBN [0001¯]/[101¯0]‖AlN nucleation layer [0001¯]/[101¯0]‖Al2O3[0001]/[112¯0]. The B composition of the AlBN layer is varied from 0% to 15% by varying the growth temperature, exploiting the reaction rate-controlled growth mechanism. X-ray diffraction and high-resolution transmission electron microscopy are used to determine the structural properties as a function of boron composition. A monotonic decrease in the c-lattice constant and a non-monotonic change in the a-lattice constant are observed with an increase in the B content in AlBN films grown on nitrided sapphire. While the control AlN film showed a bandgap of 6.1 eV, the AlBN films with ∼15% boron showed a bandgap of 5.9 eV. The AlBN films with 15% B exhibit a fivefold increase in the nonlinear second-harmonic generation intensity compared to AlN. AlBN films exhibit higher thermal conductivity than AlScN films with comparable alloy compositions, and at equal or smaller thicknesses. The findings indicate several opportunities for AlBN films in applications of deep UV optoelectronics, nonlinear photonics, and high-power electronics devices, especially in high-voltage and high-temperature environments.
Article Details
Journal Info
Journal of Applied Physics
American Institute of Physics
Authors (13)
Chandrashekhar Savant
Department of Materials Science and Engineering, Cornell University 2 , Ithaca, New York 14853,
Saurabh Vishwakarma
School for Engineering of Matter, Transport and Energy, Arizona State University 3 , Tempe, Arizona 85287,
Thai-Son Nguyen
Department of Materials Science and Engineering, Cornell University 2 , Ithaca, New York 14853,
Len van Deurzen
School of Applied and Engineering Physics, Cornell University 3 , Ithaca, New York 14853,
Joongwon Lee
School of Electrical and Computer Engineering, Cornell University 4 , Ithaca, New York 14853,
Gustavo Alvarez
Sibley School of Mechanical and Aerospace Engineering, Cornell University 5 , Ithaca, New York 14853,
Hsin Wei S. Huang
School of Electrical and Computer Engineering, Cornell University 4 , Ithaca, New York 14853,
Kazuki Nomoto
School of Electrical and Computer Engineering, Cornell University 3 , Ithaca, New York 14850,
Zhiting Tian
Sibley School of Mechanical and Aerospace Engineering, Cornell University, Ithaca, NY, USA.
Farhan Rana
School of Electrical and Computer Engineering, Cornell University 3 , Ithaca, New York 14850,
David J. Smith
Department of Physics, Arizona State University 1 , Tempe, Arizona 85287,
Huili Grace Xing
Institute of Materials and Systems for Sustainability, Nagoya University 1 , Nagoya 464-8601,
Debdeep Jena
School of Electrical and Computer Engineering, Cornell University 2 , Ithaca, New York 14853,