Electrical Characterization of As and [As+Si] doped GaN Grown by Metalorganic Chemical Vapor Deposition
- PDF / 80,941 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 34 Downloads / 247 Views
E3.19.1
Electrical Characterization of As and [As+Si] doped GaN Grown by Metalorganic Chemical Vapor Deposition M. Ahoujja,1 S. Elhamri,1 and R. Berney,1 Y.K. Yeo,2 and R. L. Hengehold2 1 2
Department of Physics, University of Dayton, Dayton, OH, USA Air Force Institute of Technology, Wright-Patterson AFB, OH, USA
ABSTRACT Electrical properties of As, Si, and [As+Si] doped GaN films grown on sapphire substrates by low temperature metalorganic chemical vapor deposition have been investigated using temperature dependent Hall-effect and deep level transient spectroscopy measurements. The Hall measurements from the GaN layers show that the concentration decreases with arsine flow (4, 40, and 400 sccm) at all temperatures. The carrier concentration of the Si-doped GaN, on the other hand, increases with the incorporation of arsine flow. This behavior is attributed to the formation of AsGa antisites which act as double donors. A deep level at around 0.82 eV below the conduction in the band gap of As doped GaN is measured by DLTS and is tentatively assigned to arsenic on gallium antisite. INTRODUCTION Throughout the last decade, GaN and related alloys have emerged as the leading materials for optoelectronic devices operating in the blue to UV spectrum. Recently, it has been shown that the introduction of arsenic impurities into GaN influences its electronic and optical properties in such a way that this semiconducting material can play an important role in future optoelectronic devices [1-7]. Bellaiche et al.[1-3] have shown via pseudopotential calculations that substitutional As isoelectronic impurity in GaN has a deep single particle energy level at 0.75 eV above the valence band. Using first-principles calculations based on density-functional theory within the local density approximation and the pseudo-potential-plane-wave method, Van de Walle et al.[4] found that under less Ga-rich conditions, As on the Ga site (AsGa) incorporation is favored and it behaves as a deep double donor. Guido et al. [5] have reported significant improvement in electron mobility and integrated photoluminescence due to As doping of GaN. Kim et al.[6] have found a room-temperature luminescence centered around 2.6 eV which they have attributed to the As impurity in GaN films. Very recently, a strong blue (2.7 eV) emission at room temperature was observed from nitrogen rich As doped GaN grown by molecular beam epitaxy [7]. In spite of these interesting observations, the study of arsenic-doped GaN (GaN:As) is still in its infancy, and, as a consequence, there are many aspects of its electronic behavior that are not well known. In the present work, the influence of arsenic doping on the electrical properties of Si doped GaN films grown on sapphire substrates by metalorganic chemical vapor deposition has been investigated using temperature dependent Hall-effect and deep-level transient spectroscopy (DLTS) measurements.
E3.19.2
EXPERIMENT Arsenic-doped GaN films were grown on sapphire substrates by metal organic chemical vapor deposition (MOCVD)
Data Loading...
