Bismuth a New Surfactant or Contact for GaN Films Grown by Molecular Beam Epitaxy

Abstract

We have investigated the influence of an additional bismuth flux during growth on the properties of GaN films prepared by plasma-assisted molecular beam epitaxy. A wide range of bismuth fluxes have been used, at the highest Bi flux this was larger than the flux of Ga. X-ray and photoluminescence studies demonstrate that the structural quality and optical properties of the GaN films grown at $800 C are practically unchanged. X-ray and Auger studies indicated that the concentration of Bi in the bulk of the films grown at $800 C is rather small. We have demonstrated that it is possible to grow conductive metallic Bi films epitaxially onto GaN films in-situ after epitaxy by reducing the deposition temperature. Bismuth may thus potentially be a new material for in-situ contacts to GaN layers and device structures.

GaN1−xBix: Extremely mismatched semiconductor alloys

“…[10][11][12] In addition, Bi in group III-V semiconductors has been used as a surfactant during growth to improve surface morphology. 13,14 Given the electronegativity, N ͑3.0͒ and Bi ͑1.8͒, as well as atomic radius, N ͑75 pm͒ and Bi ͑155 pm͒, mismatches are the largest among all group V elements, a dramatically different electronic band structure is expected to result from an N-rich GaN 1−x Bi x alloy. 15 A wide variety of crystalline semiconductor alloys have been applied to a range of technologies but silicon-based alloys have dominated the application of amorphous semiconductors.…”

Effect of TMBi supply on low-temperature MOVPE growth behavior of GaN

“…Fitouri et al reported the segregation of Bi-containing islands on the surface of GaAs 1-x Bi x grown by MOVPE at low temperature [20]. Moreover, it was reported that Bi is not incorporated in GaN matrix [6,7]. Therefore, this relative reduction <R> appears to be related to a Bi segregation on the GaN surface, which is accentuated by increasing the Bi amount in the gas phase.…”

“…Bi has been used previously as a surfactant for the growth of GaAs, In x Ga 1-x As [3],GaN x As 1-x [4]and GaInP [5]. Recently, Bi has been used as a surfactant for the growth of GaN grown at 800 °C by molecular beam epitaxy (MBE) [6].…”

Growth and transport properties of p-type GaNBi alloys

“…12 In previous work on GaN epitaxial growth, bismuth has been used as a surfactant to improve surface morphology. 13 The difference in electronegativity and atomic radii between N (3.0 eV; 75 pm) and Bi (1.8 eV; 155 pm) of 66 and 106%, respectively, is the largest among all group V elements, thus making a III-V alloy of GaNBi even more difficult to synthesize than GaNAs. 14 Because of the high electronegativity of nitrogen, the valence band (VB) of GaN is at a low energy with respect to vacuum.…”