Excitonic and deep-level emission from N- and Al-polar homoepitaxial AlN grown by molecular beam epitaxy

Abstract

Using low-temperature cathodoluminescence spectroscopy, we study the properties of N- and Al-polar AlN layers grown by molecular beam epitaxy on bulk AlN{0001}. Compared to the bulk AlN substrate, layers of both polarities feature a suppression of deep-level luminescence, a total absence of the prevalent donor with an exciton binding energy of 28 meV, and a much increased intensity of the emission from free excitons. The dominant donor in these layers is characterized by an associated exciton binding energy of 13 meV. The observation of excited exciton states up to the exciton continuum allows us to directly extract the ${\Gamma }_5$ free exciton binding energy of 57 meV.

References in corpus (9)

• Experimental Observation of High Intrinsic Thermal Conductivity of AlN
• Enhanced injection efficiency and light output in bottom tunnel-junction light-emitting diodes using UID GaN spacers
• Molecular Beam Homoepitaxy of N-polar AlN on bulk AlN substrates
• Comparison of the luminous efficiency of Ga- and N-polar In${}_x$Ga${}_{1-x}$N/In${}_y$Ga${}_{1-y}$N quantum wells grown by plasma-assisted molecular beam epitaxy
• Carrier diffusion in GaN -- a cathodoluminescence study. I: Temperature-dependent generation volume
• Luminescent N-polar (In,Ga)N/GaN quantum wells grown by plasma-assisted molecular beam epitaxy at high temperature
• Hyperspherical theory of anisotropic exciton
• Blue (In,Ga)N Light-Emitting Diodes with Buried n+-p+ Tunnel Junctions by Plasma-Assisted Molecular Beam Epitaxy
• Interface recombination in Ga- and N-polar GaN/(Al,Ga)N quantum wells grown by molecular beam epitaxy

Cited by in corpus (1)

• Chemical Vapor Deposition of Nitrides by Carbon-free Brominated Precursors