NEW PROCESSES FOR HETEROGENEOUS INTEGRATION OF III-NITRIDE OPTOELECTRONIC DEVICES: APPLICATION TO INGAN-BASED LIGHT EMITTING DIODES AND SOLAR CELLS GROWN ON 2D H-BN

Mechanical release and transfer of GaN-based heterostructures using 2D h-BN have undergone considerable development in van der Waals epitaxy of III-Nitride thin-films along with device fabrication and transfer onto various flexible and rigid substrates. The technique consists of a mechanical peeling-off of the epilayers from the native substrate, which allows a dry and fast release and transfer of optoelectronic and electronic III-N devices to arbitrary substrates. However, during the epitaxial growth and device fabrication of the epilayers, delaminations and cracks arise in the structures, which limits the size of crack-free devices to only a few hundreds of squared microns. The goal of this thesis is to develop new efficient, large-scale and low-cost new processes for heterogeneous integration of III-Nitride optoelectronic devices. These processes developed were used to fabricate lateral and vertical InGaN-based LEDs as well as nanopyramid-based InGaN solar cells grown on 2D h-BN. The outcomes of this thesis represent progress towards efficient, robust and low-cost 2D-hBN-assisted lift-off technology for heterogeneous integration of optoelectronic and electronic III-N devices.Ph.D

Design and fabrication process flow for high-efficiency and flexible InGaN solar cells

International audienc

Design and fabrication process flow for high-efficiency and flexible InGaN solar cells

International audienc

MOVPE of GaN-based mixed dimensional heterostructures on wafer-scale layered 2D hexagonal boron nitride—A key enabler of III-nitride flexible optoelectronics

International audienceWe summarize our recent progress in Metal organic vapor phase epitaxy (MOVPE) van der Waals epitaxy of wafer-scale 2D layered hexagonalboron nitride (h-BN) on sapphire and subsequently grown III-N materials. This one step growth process allows for mechanical transfer ofGaN-based devices from h-BN on sapphire to various supports. We first review the growth of h-BN on unpatterned and patterned sapphiretemplates. Second, we describe h-BN growth on dielectric pre-patterned sapphire templates, which enables dicing-free GaN-based devicestructures’ pick-and-place heterogenous integration of III-N devices. Third, we review the growth of self-assembled 1D GaN-based nanowirelight emitting diode (LED) structures on layered 2D h-BN for mechanical transfer of nanowire LEDs. Together, these results illustrate thepotential of wafer-scale van der Waals h-BN MOVPE to enhance the III-N device functionality and to improve III-N processing technology

Side-by-side comparison of pre- and post-transferred LEDs grown on 2D hexagonal boron nitride onto arbitrary substrates

International audienceWe present a critical study of LEDs on h-BN compared to the conventional LEDs on sapphire from materials characterizations, device fabrication to the device performances measurements performed before and after liftoff and transfer with and without intermediary adhesion layer to arbitrary substrates

Novel Scalable Transfer Approach for Discrete III‐Nitride Devices Using Wafer‐Scale Patterned h‐BN/Sapphire Substrate for Pick‐and‐Place Applications

International audienceThe mechanical release of III‐nitride devices using h‐BN is a promising approach for heterogeneous integration. Upscaling this technology for industrial level requires solutions that allow a simple pick‐and‐place technique of selected devices for integration while preserving device performance. An advance that satisfies both of these requirements is demonstrated in this work. It is based on a lateral control of the h‐BN quality, using patterned sapphire with a SiO2 mask, to achieve localized van der Waals epitaxy of high‐quality GaN based device structures. After process fabrication, the devices can be individually picked and placed on a foreign substrate without the need for a dicing step. In addition, this approach could reduce delamination of h‐BN on large diameter substrates because each h‐BN region is smaller, with independent device structures. Discrete InGaN LEDs on h‐BN are grown and fabricated on 2 in. patterned sapphire using a SiO2 mask. A set of devices are selectively released and transferred to flexible aluminum tape. The transferred LEDs exhibit blue light emission around 435 nm. The approach presented here is scalable on any wafer size, can be applied to other types of nitride‐based devices, and can be compatible with commercial pick‐and‐place handlers for mass production

Wafer-scale van der Waals Epitaxy of III-Nitride Devices on h-BN-An Overview of 2D/3D Epitaxy, Device Fabrication, Mechanical Release-Transfer Methods and Device Performances

Conférence invitéeInternational audienc

MOVPE growth of h-BN on patterned sapphire substrates and its application on selective area growth of GaN based LEDs structures

Conférence invitéeInternational audienc