Optical and Structural Studies of Phase Separation in InGaN Film Grown by MOCVD

Abstract

We have studied the effects of growth temperature, film thickness, and Si doping on the phase separation in InGaN films grown by metalorganic chemical vapor deposition. As the growth temperature decreased, the band-edge photoluminescence peak became splitted due to the In composition fluctuation in the InGaN film and finally separated into two discrete peaks corresponding to the epitaxial InGaN and InN-rich phase. The size and the In content of the spinodally-formed InN-rich regions increased with increasing InGaN film thickness. The Si doping was found to suppress the composition fluctuation and the In incorporation in InGaN films.

Stokes Shift and Band Gap Bowing in InxGa1-xN (0.060 ≤ x ≤ 0.105) Grown by Metalorganic Vapour Phase Epitaxy

“…Therefore, there is observed compositional inhomogeneity or strain and it should result in high line width values in In x Ga 1−x N layers. Due to the presence of strain in InGaN samples, our line width values were slightly higher than reported values by several researches [22,23]. Also, lattice mismatch between GaN and sapphire substrate are sufficient to generate misfit dislocations.…”

Depth Resolved Studies of Indium Content and Strain in InGaN Layers

“…The presence of two peaks in the InGaN diffraction profile has often been interpreted as an indication of partial phase segregation, and attributed to the presence of "micro-regions" with different In contents [8][9][10]. It is worth mentioning that these layers typically exhibit a double InGaN related luminescence peaks [11].…”

Marked suppression of In incorporation in heavily Si-doped InxGa1−xN (x ∼ 0.3) grown on GaN/α-Al2O3(0001) template

“…3 that the In composition in InGaN is markedly decreased with increasing MMSi flow rate; for example, 0.32 for 0 mol/min and 0.12 for 4.3 lmol/min MMSi. Moon et al 13 have observed a similar result, although the decrease of the In composition is a few percentage. The results shown in Fig.…”

“…Pandey et al 10 have reported Si levels in InGaN with a different In content. Several groups [11][12][13][14] have found that the Si doping gives significant effects on the growth behavior of InGaN. For example, the Si doping reduces V-defects on the InGaN surface, 11 and suppresses the m-plane and c-plane slips in InGaN/GaN heterostructures.…”

“…For example, the Si doping reduces V-defects on the InGaN surface, 11 and suppresses the m-plane and c-plane slips in InGaN/GaN heterostructures. 12 Regarding the phase separation or compositional fluctuation in InGaN, Moon et al 13 have reported that the Si doping suppresses the compositional fluctuations, while Li et al 14 have shown that the Si doping induces the phase separation. Thus, the Si doping has pronounced effects on not only electrical and optical properties but also the growth mechanism and/or the crystal structures of InGaN.…”