Single crystalline InxGa1−xN layers on germanium by molecular beam epitaxy

Abstract

In x Ga 1−x N (InGaN) alloys are predominantly grown by heteroepitaxy on foreign substrates. Most often Al 2 O 3 , SiC and Si are used as substrates, however this complicates vertical conduction from the InGaN surface to the substrate backside. Therefore we investigate the heteroepitaxial growth of InGaN layers on Ge substrates. Single crystalline InGaN was obtained and domain formation was suppressed by using a thin GaN buffer layer. The InGaN shows compressive strain, which follows from the lattice mismatch with the GaN buffer layer. The In distribution is uniform throughout the InGaN layer, with no significant In segregation within the layer. Only at the surface, in a very thin layer of 20 nm, strong In segregation is observed with about 50% In. InGaN/GaN/Ge diodes show vertical current conduction of 1 A cm −2 at −2 V. InGaN grown on Ge is therefore promising for device applications with preferred vertical conduction.

Low-cost Fabrication of Tunable Band Gap Composite Indium and Gallium Nitrides

“…Group III nitride thin films, specifically InN and GaN, have proven extremely difficult to grow under the same conditions on practical substrates, as they typically require significantly different growth temperatures: 500 °C or below for InN and above 750 °C for GaN 41 . Moreover, the successful formation of an In x Ga 1−x N alloy phase, which is highly sought after in the fields such as solar cells, LEDs and thermoelectrics, is critically dependent on the ability to grow both InN and GaN under the same conditions.…”

Epitaxial growth and characterization of high-quality aluminum films on sapphire substrates by molecular beam epitaxy

“…[17][18][19][20][21][22] In order to circumvent the issue, several technologies, such as buffer layer, epitaxial lateral overgrowth, pattern design of the Si substrates, etc., need to be used. [44][45][46][47][48][49][50][51] These technologies can reduce dislocation density and release the stress to some extent, and eventually benefit the growth of high-quality Al films on Si substrates. [44][45][46][47][48][49][50][51] Therefore, these pieces of evidence show the higher crystalline quality of Al epitaxial film grown in this work.…”

“…[44][45][46][47][48][49][50][51] These technologies can reduce dislocation density and release the stress to some extent, and eventually benefit the growth of high-quality Al films on Si substrates. [44][45][46][47][48][49][50][51] Therefore, these pieces of evidence show the higher crystalline quality of Al epitaxial film grown in this work. This achievement of higher quality Al epitaxial films mainly may be ascribed to two aspects.…”

Investigation of GaN/InGaN thin film growth on ITO substrate by thermionic vacuum arc (TVA)

“…With all these advantages, III-Nitride structures are the most suitable materials for fabrication of optoelectronic devices in blue and ultraviolet (UV) spectral regions. It is possible to grow high-quality InGaN epitaxial layers by modern crystal growth techniques such as molecular beam epitaxy (MBE) [7,9,10,13,19,20,23,30], radio frequency sputtering technique (RFSM) [11,14,16,[37][38][39] and metal organic chemical vapor deposition (MOCVD) [3-5, 17, 26, 36, 40]. The method of epitaxial crystal growth with a molecular beam involves the reaction of a thermal beam of atoms or molecules with a crystal surface in a very high vacuum environment.…”