Structural and optical properties of MOCVD InAlN epilayers

Abstract

We have studied the structural and optical properties of In x Al 1−x N alloys with compositions nearly lattice-matched to GaN. Scanning electron microscopy measurements reveals a good overall surface quality, with some defect structures distributed across the surface whose density increases with the InN concentration. On the other hand, Raman scattering experiments show three peaks in the frequency range between 500 and 900 cm −1 , which have been assigned to InN-like and AlN-like E 2 modes and A 1 (LO) mode of the In x Al 1−x N. These results agree with theoretical calculations previously reported where two-mode and one-mode behavior was predicted for the E 2 and A 1 (LO) modes, respectively. Photoluminescence and photoluminescence excitation allowed us to determine the emission and absorption energies of the In x Al 1−x N epilayers. Both energies display a redshift as the InN fraction increases. We find a roughly linear increase of the Stokes shift with InN fraction, with Stokes shift values of ≈ 0.5 eV in the composition range close to the lattice-matched condition.

Structural and Morphological Characteristics of Inxga1-xN Films Grown on SI (111) by Reactive Magnetron Sputtering

“…The A 1 (LO) mode of In X Ga 1-X N films with different In compositions manifested that the alloy films are wurtzite structure [8]. The rough curve of the main board band in the region 584~612cm -1 can attribute to the relaxation in momentum conservation and increasing lattice disorder due to the compositional inhomogeneity [9]. …”

MOVPE growth and investigation of AlInN/AlN multiple quantum wells

“…2 Other groups received comparable values using slightly different indium fractions. Hernández et al applied PL excitation spectroscopy and received a value of 4.5 eV for 16% indium [9]. Carlin et al have estimated the bandgap of Al 0.88 In 0.12 N to be between 4.7 and 4.9 eV using reflectivity measurements [6].…”

“…This indicates a high potential of AlInN also for optoelectronic applications. But still, the growth of this ternary alloy remains a challenge and yet there are only very few reports about structural and optical characterisation of this material [6,8,9]. Here, we report about the growth and optical investigation of single AlInN layers and also of AlInN/AlN multiple quantum wells (MQW), which could be used for building up efficient structures for deep-UV LEDs.…”

Cathodoluminescence of rare earth implanted AlInN

“…4,5 The band gap of Al 0.83 In 0.17 N is about 4.3 eV. 4,6 In this letter we describe a systematic investigation of AlInN as a host material for RE light emission.…”

“…6 The AlInN layer used for Eu implantation was grown at a set point of 840°C with the InN fraction estimated at 15± 2 at. %.…”