A study of the mechanisms responsible for blue emission from arsenic-doped gallium nitride

Abstract

We have investigated the influence of the growth conditions on the intensity of blue emission at room temperature from As-doped GaN samples grown by molecular beam epitaxy. A series of As-doped GaN samples was grown at 800 • C with constant fluxes of As and gallium, but with different amounts of active nitrogen. Varying the N flux allowed us to investigate films grown from strongly Ga-rich conditions to more N-rich conditions. The blue emission increases monotonically with the nitrogen flux and is most intense in the layers grown under the most nitrogen-rich conditions. This fact suggests that As atoms incorporated into the Ga sub-lattice are responsible for the strong blue emission in As-doped GaN.

On the Origin of Blue Emission from As-Doped GaN

“…(b) 228, No. 1, 213-217 (2001) proportion to one another [10]. In all of our As-doped samples, the blue emission band is observed with a maximum intensity around 2.6 eV, but the structure of the emission varies from sample to sample.…”

“…One interesting observation, with potential device applications, is the report of blue luminescence at low temperature in As-doped GaN prepared by ion implantation and in films grown by metalorganic vapour phase epitaxy [6,7]. Recently we reported strong blue luminescence at room temperature in As-doped GaN samples grown by Plasma-Assisted Molecular Beam Epitaxy (PA-MBE) [8][9][10]. As-doped GaN films might, therefore, be a suitable replacement for InGaN layers in opto-electronic devices based on growth by MBE.…”

“…In the room temperature photoluminescence (PL) spectrum from our As-doped GaN samples grown by PA-MBE [8][9][10] several peaks are observed in the near band edge region at about 3.2 and 3.4 eV together with strong blue emission at about 2.6 eV. With increasing As flux during growth, the intensity of the band edge features decrease and the blue emission intensity increases [8].…”

Spatially Resolved Cathodoluminescence Study of As Doped GaN

“…A characteristic luminescence band at 2.58 eV was observed only in the As implanted samples. This band has been observed in GaNAs layers grown by metal organic chemical vapor deposition (MOCVD) at 2.58 eV [3] and 2.5 eV [4] and layers grown by MBE at $2.6 eV [5]. In a theoretical paper, the nature of this luminescence band has been attributed to As occupying a Ga site (As Ga ) in the GaN lattice [1].…”

“…There has been a growing interest in the development of the GaNAs alloy system in recent years [1][2][3][4][5][6][7]. The prospect of reducing the bandgap of GaN by the addition of As has a major influence on the research being conducted.…”