Blue to yellow emission from (Ga,In)/GaN quantum wells grown on pixelated silicon substrate

Benjamin Damilano,Christophe Largeron,Virginie Brändli,Eric Frayssinet,Daniel Turover,Guy Feuillet,David Cooper,Marc Portail,Florian Faure

doi:10.1038/s41598-020-76031-3

Abstract

It is shown that substrate pixelisation before epitaxial growth can significantly impact the emission color of semiconductor heterostructures. The wavelength emission from InxGa1−xN/GaN quantum wells can be shifted from blue to yellow simply by reducing the mesa size from 90 × 90 µm2 to 10 × 10 µm2 of the patterned silicon used as the substrate. This color shift is mainly attributed to an increase of the quantum well thickness when the mesa size decreases. The color is also affected, in a lesser extent, by the trench width between the mesas. Cathodoluminescence hyperspectral imaging is used to map the wavelength emission of the InxGa1−xN/GaN quantum wells. Whatever the mesa size is, the wavelength emission is red-shifted at the mesa edges due to a larger quantum well thickness and In composition.

Highlights

It is shown that substrate pixelisation before epitaxial growth can significantly impact the emission color of semiconductor heterostructures
The wavelength emission increases when the trench width increases to a lesser extent than for the dependence observed as a function of the mesa size
We have shown that the wavelength emission from an InxGa1−xN/GaN multiple quantum well (MQW) grown on a micro-pixelated Si substrate can be tuned from blue (430 nm) to yellow (580 nm) depending on the pixel size and the trench width between the pixels

Summary

Introduction

It is shown that substrate pixelisation before epitaxial growth can significantly impact the emission color of semiconductor heterostructures. The wavelength emission from InxGa1−xN/GaN quantum wells can be shifted from blue to yellow by reducing the mesa size from 90 × 90 μm[2] to 10 × 10 μm[2] of the patterned silicon used as the substrate. Mixing the three basic blue/green/red colors directly on the same wafer is highly desirable and constitutes an important challenge Efforts towards this objective have been reported in the literature using for example nanowires grown by molecular beam epitaxy[5,6], light conversion by (Ga,In)N multiple quantum w ells[7], facets with different o rientations[8], and local etching of red-emitting LED s tructures[9]. Xu et al reported an enhanced indium incorporation in (Ga,In)N QWs at the corner of 340 × 340 μm[2] mesas grown on patterned silicon s ubstrate[19] but mesa-patterned silicon substrates have never been studied with the objective of modifying the emission color as a function of the mesa size

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Discussion

Conclusion