Dataset Information

Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities.

ABSTRACT: In this work, we report on the efficiency of single InGaN/GaN quantum wells (QWs) grown on thin (<1 µm) GaN buffer layers on silicon (111) substrates exhibiting very high threading dislocation (TD) densities. Despite this high defect density, we show that QW emission efficiency significantly increases upon the insertion of an In-containing underlayer, whose role is to prevent the introduction of point defects during the growth of InGaN QWs. Hence, we demonstrate that point defects play a key role in limiting InGaN QW efficiency, even in samples where their density (2-3 × 109 cm-2) is much lower than that of TD (2-3 × 1010 cm-2). Time-resolved photoluminescence and cathodoluminescence studies confirm the prevalence of point defects over TDs in QW efficiency. Interestingly, TD terminations lead to the formation of independent domains for carriers, thanks to V-pits and step bunching phenomena.

SUBMITTER: Lottigier P

PROVIDER: S-EPMC10537355 | biostudies-literature | 2023 Sep

REPOSITORIES: biostudies-literature

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Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities.

Lottigier Pierre P Di Paola Davide Maria DM Alexander Duncan T L DTL Weatherley Thomas F K TFK Sáenz de Santa María Modroño Pablo P Chen Danxuan D Jacopin Gwénolé G Carlin Jean-François JF Butté Raphaël R Grandjean Nicolas N

Nanomaterials (Basel, Switzerland) 20230916 18

In this work, we report on the efficiency of single InGaN/GaN quantum wells (QWs) grown on thin (<1 µm) GaN buffer layers on silicon (111) substrates exhibiting very high threading dislocation (TD) densities. Despite this high defect density, we show that QW emission efficiency significantly increases upon the insertion of an In-containing underlayer, whose role is to prevent the introduction of point defects during the growth of InGaN QWs. Hence, we demonstrate that point defects play a key rol ...[more]

PMID: 37764598

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Project description:Cubic InGaN alloys are a promising candidate material for next-generation optoelectronic applications as they lack internal fields and promise to cover large parts of the electromagnetic spectrum from the deep UV toward the mid-infrared. This demands high-quality epitaxial growth of cubic InGaN/GaN quantum wells, especially for the red energy range. However, the growth of indium-bearing nitride quantum wells in the metastable cubic phase still poses many challenges. InGaN and GaN are typically grown at different temperatures and with different metal fluxes in molecular beam epitaxy, leading to either long waiting periods for temperature adjustment or growth under suboptimal conditions. Both degrade the crystal quality and optical properties. In this study, we apply a metal-modulated growth approach in molecular beam epitaxy that enables us to grow either self-assembled, phase pure, cubic InGaN/GaN multi quantum wells (MQWs) or homogeneous c-InGaN layers, only by adjusting the shutter duration times for Ga and In. We achieve smooth surfaces and sharp interfaces with a quantum well thickness tunable from 6 to 16 nm and a barrier thickness ranging from 4 to 10 nm. X-ray diffraction confirms >99% phase purity of our cubic layers, while time-of-flight secondary ion mass spectrometry, scanning transmission electron microscopy, and energy-dispersive X-ray spectroscopy provide detailed information on the quantum well composition and strain. Photoluminescence measurements at room temperature demonstrate the emission properties of the samples, with the emission wavelength ranging from 540 to 670 nm. Changing the barrier and QW thickness results in a shift of emission energy of up to 400 meV, which is explained by quantum confinement and strain. The high interface quality and excellent optical properties of the quantum wells without the need for multiple metal sources or long waiting times represent a significant advance in the development of next-generation optoelectronic devices.

Dataset Information

Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities.

Publications

Investigation of the Impact of Point Defects in InGaN/GaN Quantum Wells with High Dislocation Densities.

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