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Impact of InGaN quantum wells design and composition on the performance of micro-LEDs

Technological challenge: Emerging materials and processes for nanotechnologies and microelectronics (learn more)

Department: Département d'Optronique (LETI)

Laboratory: Laboratoire des Composants Emissifs

Start Date: 01-09-2022

Location: Grenoble

CEA Code: SL-DRT-22-0465

Contact: fabian.rol@cea.fr

The growth and fabrication of InGaN/GaN blue LEDs have reached a high degree of maturity thanks to their extensive use in the field of lighting. Thanks to their robustness and high efficiency, these LEDs are seen as promising candidates to make high-luminance and high resolution micro-displays for the field of augmented reality. However, the size of µLEDs composing the pixels of micro-displays are of a few micrometers. At these dimensions, the non-radiative recombination of electrons and holes occurring on the defect present at the sidewalls becomes dominant and degrade the performances. The passivation of these defects is the usual way to recover a higher efficiency. In addition, the lateral diffusion of carriers in InGaN quantum wells (QW) should also play a role on the performance of µLEDs by controlling the migration of electron and holes to the defective sidewalls. Over the last 10 years, researchers have gained a much better understanding of the physics of InGaN QW in large LEDs and they have optimized the epi-structures accordingly. However, going from macro to micro-LEDs have created new constraints (mainly the non-radiative recombination at the sidewalls). For this PhD, we propose to study the impact of InGaN QW design and composition on carrier diffusion properties and their impact on the performance of µLEDs. The student will be in charge of growing quantum wells and complete LEDs structures by MOCVD and will characterize them thoroughly. A large part of the PhD will be dedicated to the spectroscopic and electro-optical characterization of the samples that will be completed by structural characterization.

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