Systematic study on dynamic atomic layer epitaxy of InN on/in +c-GaN matrix and fabrication of fine-structure InN/GaN quantum wells: Role of high growth temperature

Abstract

The growth kinetics and properties of nominally 1-ML (monolayer)-thick InN wells on/in +c-GaN matrix fabricated using dynamic atomic layer epitaxy (D-ALEp) by plasma-assisted molecular beam epitaxy were systematically studied, with particular attention given to the effects of growth temperature. Attention was also given to how and where the ∼1-ML-thick InN layers were frozen or embedded on/in the +c-GaN matrix. The D-ALEp of InN on GaN was a two-stage process; in the 1st stage, an “In+N” bilayer/monolayer was formed on the GaN surface, while in the 2nd, this was capped by a GaN barrier layer. Each process was monitored in-situ using spectroscopic ellipsometry. The target growth temperature was above 620 °C and much higher than the upper critical epitaxy temperature of InN (∼500 °C). The “In+N” bilayer/monolayer tended to be an incommensurate phase, and the growth of InN layers was possible only when they were capped with a GaN layer. The InN layers could be coherently inserted into the GaN matrix under self-organizing and self-limiting epitaxy modes. The growth temperature was the most dominant growth parameter on both the growth process and the structure of the InN layers. Reflecting the inherent growth behavior of D-ALEp grown InN on/in +c-GaN at high growth temperature, the embedded InN layers in the GaN matrix were basically not full-ML in coverage, and the thickness of sheet-island-like InN layers was essentially either 1-ML or 2-ML. It was found that these InN layers tended to be frozen at the step edges on the GaN and around screw-type threading dislocations. The InN wells formed type-I band line-up heterostructures with GaN barriers, with exciton localization energies of about 300 and 500 meV at 15 K for the 1-ML and 2-ML InN wells, respectively.

Analysis of InGaN-Delta-InN Quantum Wells on InGaN Substrates for Red Light Emitting Diodes and Lasers

“…While we have calculated the spectra for delta-layer thicknesses between 1 and 8 Å in increments of 1 Å, it is important to note that a single InN monolayer (ML) is approximately 3 Å thick [46][47][48][49]. While precision growth of single (3 Å) and double (6 Å) monolayers of InN has been demonstrated through use of both metal organic chemical vapor deposition (MOCVD) and molecular beam epitaxy (MBE) [46][47][48][49], the growth of InN fractional monolayers (FMLs), for example a 4 Å (4/3 ML) layer, is more difficult, as a variety of complex growth conditions effect the long-and short-range order of the incomplete top monolayer [47][48][49]. While Fig.…”

Strain-Induced Band Gap Variation in InGaN/GaN Short Period Superlattices

“…Another issue pertains to the influence on the band gap of a possible compositional inhomogeneity of the In x Ga 1−x N quantum wells due to local phase separation into InN and GaN [24]. This relates to the suggestion regarding an inhomogeneous distribution of the indium content [16]. Toward these aims, we have performed density functional theory (DFT) calculations of monolayer-thick In x Ga 1−x N quantum wells on strained barriers, as well as calculations of phase-separated monolayer-thick quantum wells.…”

Electronic and Optical properties of Metallic Nitride: A comparative study between the MN (M=Al, Ga, In, Tl) monolayers

“…Moreover, several InN nanostructures, such as InN nanotubes, nanowires [23,24], and monolayer InN quantum wells [25], have been experimentally synthesized. Although TlN has not been prepared, a theoretical investigation using DFT indicated that it has the same structure as other metal nitrides [26][27][28], implying that it might be synthesized.…”