Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

Liu, Shangfeng; Yuan, Ye; Sheng, Shanshan; Wang, Tao; Zhang, Jin; Huang, Lijie; Zhang, Xiaohu; Kang, Junjie; Luo, Wei; Li, Yongde; Wang, Houjin; Wang, Weiyun; Xiao, Chuan; Liu, Yaoping; Wang, Qi; Wang, Xinqiang

doi:10.1088/1674-4926/42/12/122804

Cited by 17 publications

(10 citation statements)

References 39 publications

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“…High-temperature annealing has been proposed as an effective approach to improving the crystallinity of hBN and the crystal quality of AlN. [39][40][41][42] We have also performed high-temperature annealing at 1600 °C in the same MBE chamber for the hBN samples grown at lower temperatures. However, the morphology of hBN nanoribbons, as well as the above-mentioned BN nanoparticles, barely change, which is attributed to the robust thermal stability of BN.…”

Section: Interface-mediated Synthesis Of Monolayer Hbnmentioning

confidence: 99%

Scalable Synthesis of Monolayer Hexagonal Boron Nitride on Graphene with Giant Bandgap Renormalization

et al. 2022

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as fundamental building blocks of such 2D devices. Specifically, vertically stacked hBN/ graphene (hBN/G) van der Waals (vdW) heterostructures have been successfully employed to produce emergent properties, such as quantum Hall effect, [8] Hofstadter butterfly spectrum, [9] and plasmon and phonon polaritons. [10] Complementary to the vertical hBN/G vdW heterostructure, the in-plane version forms a covalent hBN/G heterostructure with equally attractive properties, such as transitions between semiconducting, half-metallic, and metallic phases, spin polarization magnetism, and exotic electronic states, [11][12][13][14][15] or even the possibility to reconstruct electronic interfaces similar to those observed in oxide heterostructures. [16,17] The scope of these fascinating properties could be radically expanded by demonstrating epitaxially grown monolayer hBN on graphene with superior structural, electrical, and optical properties, as well as precise control of both the hBN/G out-ofplane and in-plane monolayer interfaces.Recently, intensive efforts have been devoted to the epitaxial growth of hBN on metals, [18][19][20] sapphire, [21] and graphene substrates [22] by using sputtering, [23] chemical vapor deposition (CVD), [24] metal-organic chemical vapor deposition (MOCVD), [25] and molecular beam epitaxy (MBE). [26] Due to the Monolayer hexagonal boron nitride (hBN) has been widely considered a fundamental building block for 2D heterostructures and devices. However, the controlled and scalable synthesis of hBN and its 2D heterostructures has remained a daunting challenge. Here, an hBN/graphene (hBN/G) interface-mediated growth process for the controlled synthesis of high-quality monolayer hBN is proposed and further demonstrated. It is discovered that the in-plane hBN/G interface can be precisely controlled, enabling the scalable epitaxy of unidirectional monolayer hBN on graphene, which exhibits a uniform moiré superlattice consistent with single-domain hBN, aligned to the underlying graphene lattice. Furthermore, it is identified that the deep-ultraviolet emission at 6.12 eV stems from the 1s-exciton state of monolayer hBN with a giant renormalized direct bandgap on graphene. This work provides a viable path for the controlled synthesis of ultraclean, wafer-scale, atomically ordered 2D quantum materials, as well as the fabrication of 2D quantum electronic and optoelectronic devices.

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Section: Interface-mediated Synthesis Of Monolayer Hbnmentioning

confidence: 99%

Scalable Synthesis of Monolayer Hexagonal Boron Nitride on Graphene with Giant Bandgap Renormalization

et al. 2022

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“…Since the inherent lattice and TEC mismatch between AlN and sapphire substrate (a positive lattice mismatch of +13.3% and a negative TEC mismatch of −44%) 18 , 19 , crystal defects will inevitably be introduced into the AlN layer in the epitaxial process 20 – 22 and the formed large residual strain severely limits the performance of the device 23 . Therefore, an excellent solution is needed to release the large residual strain of the epilayer, so as to realize the high-quality growth of the heteroepitaxial AlN film and meet the application requirements of DUV optoelectronic devices.…”

Section: Discussionmentioning

confidence: 99%

“…Currently, due to the lack of large-size and low-price homogenous substrates, the optimal choice to grow AlN films is usually to perform heteroepitaxial growth on sapphire 14 – 17 . Unfortunately, due to the inherent lattice and thermal expansion coefficient (TEC) mismatches between AlN and sapphire substrate 18 , 19 , even the well-known two-step epitaxy method or epitaxial lateral overgrowth (ELO) technology still inevitably introduces a variety of crystal defects into AlN epilayer 20 – 22 . In particular, the large residual strain in the AlN film leads to the nonuniformity of the Al distribution in the upper AlGaN layer accompanied by wafer bending, which severely limits the device performance 23 , 24 .…”

Section: Introductionmentioning

confidence: 99%

Graphene-driving strain engineering to enable strain-free epitaxy of AlN film for deep ultraviolet light-emitting diode

et al. 2022

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The energy-efficient deep ultraviolet (DUV) optoelectronic devices suffer from critical issues associated with the poor quality and large strain of nitride material system caused by the inherent mismatch of heteroepitaxy. In this work, we have prepared the strain-free AlN film with low dislocation density (DD) by graphene (Gr)-driving strain-pre-store engineering and a unique mechanism of strain-relaxation in quasi-van der Waals (QvdW) epitaxy is presented. The DD in AlN epilayer with Gr exhibits an anomalous sawtooth-like evolution during the whole epitaxy process. Gr can help to enable the annihilation of the dislocations originated from the interface between AlN and Gr/sapphire by impelling a lateral two-dimensional growth mode. Remarkably, it can induce AlN epilayer to pre-store sufficient tensile strain during the early growth stage and thus compensate the compressive strain caused by hetero-mismatch. Therefore, the low-strain state of the DUV light-emitting diode (DUV-LED) epitaxial structure is realized on the strain-free AlN template with Gr. Furthermore, the DUV-LED with Gr demonstrate 2.1 times enhancement of light output power and a better stability of luminous wavelength compared to that on bare sapphire. An in-depth understanding of this work reveals diverse beneficial impacts of Gr on nitride growth and provides a novel strategy of relaxing the vital requirements of hetero-mismatch in conventional heteroepitaxy.

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“…Numerous methods have been adopted to address the aforementioned challenges during the growth of high-quality AlN, including substrate pretreatment, , utilization of low-temperature nucleation layer (NL), − and optimization of growth conditions. − Among various factors, choosing appropriate NL is vital for the subsequent AlN growth since it can provide a transition layer lattice mismatch to AlN, alleviating thermal strain and suppressing the formation of three-dimensional hillocks. , Recently, AlN NL prepared by physical vapor deposition (PVD) has been widely utilized for the growth of III-nitride thin films. ,,, Thanks to the nonequilibrium growth condition, uniform nucleated grains from the magnetron sputtering technique can be achieved compared with metal–organic chemical vapor deposition (MOCVD). A significantly reduced screw-type threading dislocation density in the epitaxial layer was obtained. , With the introduction of postgrowth thermal annealing, the full width at half-maximum (FWHM) value of the (0002) rocking curve diffraction scan can be reduced to as low as 12 arcsec .…”

Section: Introductionmentioning

confidence: 99%

Evolution of Dislocations and Strains in AlN Grown by High-Temperature Metal–Organic Chemical Vapor Deposition

Chen,

Gao,

Chen

et al. 2024

Crystal Growth & Design

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High-quality aluminum nitride (AlN) templates are essential for the development of optoelectronic and electronic devices. Here, the evolution of strains and dislocations during AlN epitaxy on commercially available sputtered AlN/sapphire substrates was comprehensively investigated. The presence of small and uniform grains in the sputtered AlN nucleation layer (NL) results in smaller strain levels and fewer dislocations at the interface during metal−organic chemical vapor deposition (MOCVD) of a high-temperature AlN thin film. Dislocations are annihilated in the form of dislocation loops or undergo 90°bending, contributing to better crystalline quality compared to AlN grown on NL prepared by MOCVD. However, a higher strain level was identified in AlN grown on sputtered NLs, where the strain was released through thin film cracking. Modulation of different stages during AlN growth is necessary toward a balance between thin film quality and strain relaxation.

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Four-inch high quality crack-free AlN layer grown on a high-temperature annealed AlN template by MOCVD

Cited by 17 publications

References 39 publications

Scalable Synthesis of Monolayer Hexagonal Boron Nitride on Graphene with Giant Bandgap Renormalization

Scalable Synthesis of Monolayer Hexagonal Boron Nitride on Graphene with Giant Bandgap Renormalization

Graphene-driving strain engineering to enable strain-free epitaxy of AlN film for deep ultraviolet light-emitting diode

Evolution of Dislocations and Strains in AlN Grown by High-Temperature Metal–Organic Chemical Vapor Deposition

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