Transferable GaN Enabled by Selective Nucleation of AlN on Graphene for High‐Brightness Violet Light‐Emitting Diodes

Abstract

some outstanding features, such as a high carrier mobility, [8][9][10] a high thermal conductivity, [11] flexibility, [12] and visible transparency. [13,14] Moreover, it can be used as a removable layer for the epitaxial growth of III-Ns, thus providing the foundation for a new field of transferable and flexible LEDs. [15,16] Recently, graphene has been used as a buffer layer for the van der Waals epitaxy growth of a GaN epilayer to overcome the substantial thermal expansion coefficient and in-plane lattice constant mismatch between the GaN epilayer and sapphire substrate (c-Al 2 O 3 ), which causes a significant strain in the GaN epilayer. However, because the graphene surface lacks dangling bonds, the nucleation of nitrides on graphene is restricted, and clusters are easily formed. [17,18] In this study, theoretical calculations using first-principles calculations based on density functional theory (DFT) were carefully conducted to further examine the formation mechanism of AlN and GaN on graphene. We found that AlN selectively grows on graphene, and we identified its optimal nucleation site. We obtained the adsorption probability of Al atoms at various positions on the graphene CC ring and found that the hollow of the complete graphene CC ring and the center of the broken graphene CC ring are the best adsorption positions under different states of the graphene. Based on this, we innovatively inserted an AlN composite nucleation layer between graphene and GaN, which was grown by metal organic chemical vapor deposition (MOCVD) using time-distributed and constant-pressure (TDCP) growth. The growth process for AlN is divided into three stages. Under the same pressure, different flow rates, and growth temperatures are used for each stage. By controlling the growth time at different flow rates, an AlN composite nucleation layer on graphene can be formed. By introducing the selective nucleation of an AlN composite layer and graphene, the biaxial stress of the GaN film was effectively released, leading to transferable and low density dislocations in the GaN film and the In 0.1 Ga 0.9 N/GaN multiple quantum well structures. Note that LEDs with an ultrahigh light output power (LOP) of 260.5 mW at a small current of 560 mA were achieved. Our study demonstrates a practical application of an AlN composite nucleation layer grown on graphene that may result in A transferable GaN epilayer is grown on an improved aluminum nitride (AlN)/graphene composite substrate. In this study, theoretical calculations using first-principles calculations based on density functional theory are carefully conducted to further examine the formation mechanism of AlN on graphene. AlN selectively grows on graphene via its optimal nucleation site, which leads to the selective nucleation of AlN on graphene via quasi-van der Waals epitaxy. Thus, an AlN composite nucleation layer is innovatively inserted between graphene and GaN, using the time-distributed and constant-pressure growth method by metal organic chemical vapor deposition. Moreover, a hi...

Layer-Scale and Chip-Scale Transfer Techniques for Functional Devices and Systems: A Review

“…2D layer-assisted delamination exploits the weak adhesion of the thin layer grown on layered 2D semiconductors [ 78 , 191 , 192 , 193 , 194 , 195 , 196 , 197 , 198 , 199 , 200 , 201 , 202 , 203 , 204 , 205 , 206 , 207 ]. This technique is also referred to as van der Waals (VDW) epitaxy [ 207 ] ( Figure 9 ).…”

“…Thanks to the advancement in epitaxial growth, VDW growth of high-quality III-nitride on such 2D semiconductor layers has been demonstrated, despite the large lattice mismatch. Various 2D layered materials, such as boron nitride [ 194 , 195 , 198 , 200 ] and graphene [ 78 , 191 , 192 , 193 , 196 , 197 , 199 , 201 , 202 , 203 , 204 , 205 , 206 ], have been explored to assist the lift-off of the thin semiconductor layers grown on 2D layered materials.…”

A Bright and Stable Violet Carbon Dot Light‐Emitting Diode

“…The cheap and stable violet emission materials and their violet light‐emitting diodes (LEDs) have been under a great requirement for sterilization, light fidelity, display technology, and anticounterfeit and biology medical treatment. [ 1–7 ] Generally, the violet light is mainly from noble gases such as deuterium, mercury, and xenon lamps, which are heavy and inconvenient for application. [ 2 ] Some wide band‐gap semiconductors, such as gallium nitride and indium gallium nitride, are used for violet LEDs, which are irreversible harm to people and quite expensive.…”

“…[ 1–7 ] Generally, the violet light is mainly from noble gases such as deuterium, mercury, and xenon lamps, which are heavy and inconvenient for application. [ 2 ] Some wide band‐gap semiconductors, such as gallium nitride and indium gallium nitride, are used for violet LEDs, which are irreversible harm to people and quite expensive. [ 8,9 ] Recently, Cd 2+ or Pb 2+ based colloidal semiconductor quantum dots (QDs) have emerged as candidates for efficient violet LEDs.…”

Epitaxial Growth of GaN on Magnetron Sputtered AlN/Hexagonal BN/Sapphire Substrates

“…The van der Waals epitaxy of III-nitrides on two-dimensional materials has been a hot research topic in recent years [ 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. The two-dimensional material h-BN serves as an ideal layer for mechanically releasing devices from the substrate [ 20 ].…”