Optical study of phase-separated thick InGaN layers grown on a compliant substrate

Abstract

The optical properties of thick InGaN layers grown on a compliant substrate (CS) were investigated. The CS was fabricated by thermal deformation of nanoporous GaN during high-temperature annealing. The strain sharing between the InGaN with CS was characterized using high-resolution X-ray diffraction, and we found a reduced in-plane strain of the InGaN on the CS. Photoluminescence (PL) spectra exhibited double peaks associated with discontinuous strain relaxation during the growth of the InGaN films. The strain sharing suppressed defect formation in the InGaN grown on CS, whereas the degree of indium fluctuation was similar because the phase separation resulted from spinodal decomposition. The temperature dependence of the PL spectra and internal quantum efficiency were analyzed as a function of the thickness of the InGaN layer. The effects of the CS on the growth of thick InGaN layers are discussed.

Suppression of indium-composition fluctuations in InGaN epitaxial layers by periodically-pulsed mixture of N 2 and H 2 carrier gas

“…However, the peak position and line shape cannot be precisely determined due to the oscillations caused by the interference effect appearing usually in InGaN layers. [11,27] Figure 2 shows the optical transmission spectra of the three samples. By increasing the duration time, the main absorption edge of InGaN around 425 nm is slightly blue-shifted.…”

“…For example, The CLT of an In x Ga 1−x N epilayer with x > 10% is calculated to be less than 100 nm. [11] When the thickness of InGaN epilayer exceeds the CLT, strain relaxation accompanied by the formation of dislocations may occur. Therefore, it is difficult to prepare high crystalline quality In-GaN epilayers with In-content > 10% and thickness > 100 nm due to the severe In-fluctuations and high defect density.…”

Transparent, Flexible Piezoelectric Nanogenerator Based on GaN Membrane Using Electrochemical Lift-Off

“…The EC etching of GaN has been actively studied to chemically lift off a GaN device from the substrate. ,, The etching behavior strongly depends on the doping concentration and anodic bias; a high doping concentration and large anodic bias lead to completely etching a highly conductive sacrificial layer. In our design, due to the large difference between the conductivities of the u-GaN and n + -GaN layers, n + -GaN was selectively etched at the applied voltage of 30 V, as shown in Figure a.…”

Influence of InGaN interlayer thickness on GaN layers grown by metal organic chemical vapour deposition

“…These V-pits have been observed as inverted pyramids along with (1 0 -1 1) faceted sidewalls [10]. The reduction in V-pits can be attained when the In composition or InGaN thickness is within its critical value, which improves the interfaces of the InGaN and helps in suppressing the alloy disorders [11]. The In incorporation, strain induced bandgap, interfaces, structural quality and annealing effect on the InGaN based structures were already briefly discussed in the literature [3, 4, 12, 13].…”