Growth and Properties of InGaN and AlInGaN Thin Films on (0001) Sapphire

Abstract

High quality InGaN films have led to the development of LEDs and blue lasers. The quaternary AlInGaN however, represents a more versatile material since the bandgap and lattice constant can be independently varied. We report on such films grown on (0001) sapphire substrates in an atmospheric pressure MOCVD reactor at 750-800°C. The ternary films have a composition of up to 40% InN and the quaternary films were grown in the composition range of 0 to 20% AlN and 0 to 20% InN. The quaternary compositions studied by EDS and the lattice constants from double crystal XRD followed Vegard's law indicating solid solubility for the range studied. Room temperature PL is dominated by band edge emission for InGaN and AlInGaN, at low AlN%. Higher AlN alloys of AlInGaN had PL dominated by deep levels. AlInGaN/InGaN and AlGaN/InGaN heterostructures were grown with abrupt interfaces. We emphasize the most important growth parameters for the growth of high quality ternary and quaternary thin films. The structural, electrical and optical properties of these In-based ternary and quaternary films and their lattice matched and strained heterostructures will also be presented.

GaN and GaxIn1−xN Nanoparticles with Tunable Indium Content: Synthesis and Characterization

“…From this figure, it is seen that the peak positions of the Ga‐In‐N samples are shifted to lower angles compared with those of pure GaN, suggesting an increase in the lattice constants as a result of the substitution of smaller Ga 3+ ions with bigger In 3+ ions. Similar effects were found in the systems of Al‐Y‐N, Al‐Sc‐N, and Al‐Ga‐N 2. 33, 34 The progressive peak shifts toward lower angles upon increasing the indium loading supports the ternary nature of the as‐prepared Ga‐In‐N samples, rather than mixtures of the GaN and InN phases.…”

Optical study of AlGaN/GaN based HEMT structures grown on sapphire and SiC

“…The features around 3.4 eV correspond to the GaN buffer layer. For all samples (1)(2)(3)(4)(5)(6), the shape and the intensity of this line are almost the same. At about 4.0 eV, we can observe significant differences for the features corresponding to the AlGaN capping layer.…”

“…The most common Al content in the top layer of HEMT structure is about x = 30%. Due to the large lattice mismatch to GaN (m = 1.5%) [1] the critical thickness of ternary Al 0.3 Ga 0.7 N compound is placed around 24 nm. Below this thickness, the Al 0.3 Ga 0.7 N layer has a pseudomorphic nature; while the Al 0.3 Ga 0.7 N layer is relaxed or at least partially relaxed for thicknesses above this critical thickness.…”

Long‐Term UV Detecting Wearable Patches Enabled by III‐N Compound Semiconductor‐Based Microphotodetectors

“…Therefore, we controlled the growth temperature to acquire the targeted UV-A bandgap (3.1-2.91 eV), as shown in Figure S1 in the Supporting Information. [24,25] iii) A mesa structure of InGaN/u-GaN was patterned by inductively coupled plasma-reactive ion etching (ICP-RIE), producing 150 × 150 μm 2 sized photodetector chips. iv) After the dry etching process, the μPDs were isolated using UV-cured epoxy (SU-8, thickness of ≈5 μm) and interconnected with Cr/Au-based IDEs to fabricate an InGaN/GaN Schottky diode with an increased active surface area.…”