Heterogeneous Integration of Thin-Film InGaN-Based Solar Cells on Foreign Substrates with Enhanced Performance

Abstract

A practical III-nitride photovoltaic (PV) application consists of transfer to a foreign substrate with enhanced functionality and integration with mature group IV or III−V based solar cell technologies. This requires a lift-off technique compatible with good quality III−N materials, with photovoltaic device fabrication and with subsequent bonding on a heterogeneous substrate. Here, we demonstrate the first InGaN-based solar cells on a 2 in. h-BN/sapphire wafer and their transfer to glass with a backside reflector. III−N solar cells with various sizes and designs are processed and characterized on a full 2 in. wafer giving performances comparable to similar devices on sapphire. The subsequent crack-free transfer of the solar cells, enabled by Van der Waal bonded 2D layered h-BN, to a substrate with a backside reflector yields an increase in the short circuit current density of up to 20%. This demonstration of transferred InGaN-based solar cells on foreign substrates while increasing performance represents a major advance toward lightweight, low cost, and high efficiency photovoltaic applications.

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

“…Recently, different high-quality GaN-based device structures, such as InGaN and AlGaN light emitting diodes (LEDs) and high electron mobility transistors (HEMTs), were grown on h-BN, and the transfer to arbitrary substrates has been demonstrated. 18,38,39 GaN on BN was structurally similar to GaN on graphene reported elsewhere, 15 and the total threading dislocation density was around 1 × 10 9 cm −3 . The quality of GaN is improved by reducing the h-BN thickness.…”

Recent Advances in Mechanically Transferable III‐Nitride Based on 2D Buffer Strategy

“…[90] However, the lattice mismatch between InN and GaN makes it experimentally challenging to grow high-quality In-rich InGaN films. The first transferable InGaN-based solar cell was prepared in 2018 by Ayari et al [91] using vdWE. The devices were exfoliated from a h-BN/sapphire template with a commercially available water-dissolvable tape, and then bonded to a glass slab with a backside reflector using a polyurethane-based transparent resin.…”

Monolithic Free-Standing Large-Area Vertical III-N Light-Emitting Diode Arrays by One-Step h-BN-Based Thermomechanical Self-Lift-Off and Transfer

“…However, these techniques have some limitations such as high capital cost for laser lift-off, slowness of a time-consuming process for chemical lift-off, and a low ability to reuse the substrate , for both laser and chemical lift-off. Recently, a promising transfer approach based on two-dimensional crystals, namely graphene , and hexagonal boron nitride (h-BN), , has emerged as an effective technology for the release and transfer of III-nitride epilayers. This approach consists of a mechanical peeling-off of epilayers from the substrate, which allows a dry and fast (instantaneous) release.…”