Journal of Crystal Growth最新文献_第2页

Microstructural evolution and crystalline behavior in silicon carbide nano-powder during selective laser melting: A molecular dynamics simulation 选择性激光熔化过程中碳化硅纳米粉体的微结构演变和结晶行为：分子动力学模拟

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-11-02 DOI: 10.1016/j.jcrysgro.2024.127985

Amin Hamed Mashhadzadeh , Maryam Zarghami Dehaghani , Haris Doumanidis , Boris Golman , Konstantinos V. Kostas , Christos Spitas

Silicon carbide (SiC), with its isotropic three-dimensional diamond lattice structure, emerges as a promising candidate for SiC device production through selective laser melting (SLM). The appeal lies in its simplified fabrication process, coupled with outstanding thermal properties, high hardness, and remarkable wear resistance. This potential of SiC in SLM not only streamlines the fabrication process but also harnesses the exceptional properties inherent in SiC. In this study, we utilized molecular dynamics (MD) simulations to model the SLM process. A nanopowder bed made up of approximately half a million atoms of SiC was simulated as a two-layer quasi-2D system. Controlled heating of SiC meltpools, slightly surpassing the melting temperature, facilitated the monitored coalescence of nano-powders, resulting in successful melting and the formation of continuous domains within the meltpools. The observed reduction in crystalline structures is due to the elevated thermal energy imparted to the SiC atoms during the heating process, which disrupts the atomic arrangement and leads to a transition from crystalline to amorphous states. The subsequent solidification process, characterized by a high cooling rate, led to the establishment of final amorphous solidified domains. Looking ahead, our research aims to delve into exploring the structural and functional characteristics of the produced SiC devices, evaluating their potential applications across diverse technological domains.

碳化硅（SiC）具有各向同性的三维金刚石晶格结构，是通过选择性激光熔融（SLM）生产碳化硅器件的理想候选材料。其吸引力在于简化的制造工艺，以及出色的热性能、高硬度和显著的耐磨性。碳化硅在 SLM 中的这种潜力不仅简化了制造工艺，而且还利用了碳化硅固有的优异特性。在本研究中，我们利用分子动力学（MD）模拟对 SLM 过程进行建模。由大约 50 万个 SiC 原子组成的纳米粉体床被模拟为一个双层准二维系统。受控加热碳化硅熔池，使其温度略高于熔化温度，促进了纳米粉体的监控凝聚，从而成功熔化并在熔池中形成连续的畴。所观察到的晶体结构减少是由于在加热过程中向碳化硅原子传递的热能升高，破坏了原子排列，导致从晶体态过渡到非晶态。随后的凝固过程以高冷却速度为特征，导致最终非晶凝固域的形成。展望未来，我们的研究旨在深入探索所生产的碳化硅器件的结构和功能特性，评估其在不同技术领域的潜在应用。

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引用次数: 0

Ammonia-free quasi-atmospheric MOCVD of InN/Al2O3 (0001) InN/Al2O3 (0001) 的无氨准大气 MOCVD

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-11-02 DOI: 10.1016/j.jcrysgro.2024.127980

Hisashi Yamada , Tokio Takahashi , Takahiro Gotow , Naoto Kumagai , Tetsuji Shimizu , Toshihide Ide , Tatsuro Maeda

We demonstrate ammonia-free quasi-atmospheric metal–organic chemical vapor deposition (AFQA-MOCVD) of InN grown on c-plane sapphire (Al₂O₃) substrate using high-density nitrogen (N₂) microstrip-line microwave plasma. Dependence of growth temperature (T_g) and N₂ plasma power on structural properties were examined. Increasing T_g and N₂ plasma power markedly improved surface morphology of InN. An atomically smooth surface with layer-by-layer growth mode was realized at T_g of 750 °C under N₂ plasma power of 80 W. Fully strain-relaxed InN was grown on in-plane crystal rotation by 30° with respect to the Al₂O₃ (0001). N-polar InN on Al₂O₃ (0001) was revealed by scanning transmission electron microscopy. AFQA-MOCVD enables to expand growth windows by increasing T_g and V/III ratio compared to the standard MOCVD using NH₃.

我们展示了利用高密度氮气（N2）微带线微波等离子体在 c 平面蓝宝石（Al2O3）衬底上生长的无氨准大气层金属有机化学气相沉积（AFQA-MOCVD）技术。研究了生长温度（Tg）和 N2 等离子体功率对结构特性的影响。提高 Tg 和 N2 等离子功率可明显改善 InN 的表面形态。相对于 Al2O3 (0001) 的面内晶体旋转 30°，生长出了完全应变松弛的 InN。扫描透射电子显微镜显示了 Al2O3 (0001) 上的 N 极 InN。与使用 NH3 的标准 MOCVD 相比，AFQA-MOCVD 能够通过提高 Tg 和 V/III 比率来扩大生长窗口。

引用次数: 0

Transferrable GaN-based Micro-LED heterostructures grown on h-BN for optogenetic applications 在 h-BN 上生长的可转移 GaN 基微型 LED 异质结构用于光遗传学应用

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-11-02 DOI: 10.1016/j.jcrysgro.2024.127979

T.M. Tran , A. Kassem , V. Ottapilakkal , P. Vuong , R. Gujrati , M. Bourras , A. Srivastava , A. Perepeliuc , T. Moudakir , S. Gautier , S. Bouchoule , M. Tchernycheva , P.L. Voss , S. Sundaram , J.P. Salvestrini , A. Ougazzaden

Individually transferrable GaN-based MQWs micro-LED structures grown on two-dimensional (2D) hexagonal boron nitride (h-BN) have been demonstrated. Different sizes (60 × 30 µm, 60 × 60 µm, 90 × 60 µm and 90 × 90 µm) of GaN-based LED heterostructures on layered h-BN were grown on dielectric SiN patterned sapphire substrates using Metal Organic Vapor Phase Epitaxy (MOVPE). Scanning electron microscope (SEM) images show micro-LEDs were grown with high selectivity within the mask opening areas. Consistent MQWs emission from micro-LEDs was observed at 452 ± 2 nm by cathodoluminescence (CL) spectroscopy for all micro-LED sizes. The structural and optical quality were similar to the GaN-based-LEDs grown on unpatterned substrates. In addition, we have successfully demonstrated the lift-off and transfer of individual micro-LEDs to arbitrary flexible templates using a transfer printing machine, which can be addressed by full front-end process. These studies highlight the role of combination of van der Waals (vdW) epitaxy and selective area growth (SAG) in facilitating the direct realization of dimensionally defined III-Nitride micro-LED structures and the mechanical release and transfer of these micro-LEDs to templates suitable for flexible display and optogenetics applications.

在二维（2D）六方氮化硼（h-BN）上生长的可单独转移的氮化镓基 MQW 微型 LED 结构已经得到证实。利用金属有机气相外延（MOVPE）技术，在介电质SiN图案化蓝宝石衬底上生长出了不同尺寸（60 × 30 µm、60 × 60 µm、90 × 60 µm和90 × 90 µm）的层状氮化硼氮化镓基 LED 异质结构。扫描电子显微镜 (SEM) 图像显示，在掩膜开口区域内生长的微型 LED 具有很高的选择性。通过阴极发光（CL）光谱，观察到所有尺寸的微型 LED 在 452 ± 2 nm 处发出一致的 MQW。其结构和光学质量与在无图案衬底上生长的氮化镓基发光二极管相似。此外，我们还成功演示了使用转移印花机将单个微型 LED 抬起并转移到任意柔性模板上，这可以通过完整的前端工艺来实现。这些研究凸显了范德华（vdW）外延和选择性面积生长（SAG）相结合在促进直接实现尺寸确定的 III 氮化物微 LED 结构以及将这些微 LED 机械释放和转移到适合柔性显示和光遗传学应用的模板方面的作用。

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引用次数: 0

Hydrothermal growth of potassium tantalate niobate crystals 钽酸铌酸钾晶体的水热生长

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-10-30 DOI: 10.1016/j.jcrysgro.2024.127983

Jingfang Tong , Haitao Zhou , Huajian Yu , Wenyuan Wu , Xudong Song , Weidi Zhao , Changlong Zhang , Xuping Wang

Potassium tantalum niobate (KTa_1−xNb_xO₃, KTN) is a solid-solution crystal composed of potassium tantalate and potassium niobate, known for exhibiting the most substantial quadratic electro-optic effect recorded to date. The properties and crystallographic phases of KTN, varying from cubic (paraelectric) to tetragonal or orthorhombic (ferroelectric), are critically dependent on the tantalum-to-niobate ratio and the material’s homogeneity. KTN in the cubic phase, particularly near the cubic-tetragonal phase boundary, exhibits a high electro-optic coefficient, making it highly suitable for holographic storage applications. We employed both the cooling hydrothermal method and the temperature-difference hydrothermal method to obtain KTa_1−xNb_xO₃ (x = 0.37) crystals with uniform composition and high quality.

铌酸钽钾（KTa1-xNbxO3，KTN）是一种由钽酸钾和铌酸钾组成的固溶体晶体，因显示出迄今为止最显著的二次电光效应而闻名。钽铌酸钾的性质和结晶相从立方（顺电）到四方或正方（铁电）不等，主要取决于钽铌酸钾的比例和材料的均匀性。立方相的 KTN，尤其是在立方-四方相边界附近，具有很高的电光系数，因此非常适合全息存储应用。我们采用冷却水热法和温差水热法获得了成分均匀、质量上乘的 KTa1-xNbxO3 (x = 0.37) 晶体。

引用次数: 0

Evaluation of AlN insertion layer on the properties of heterogeneous integrated Ga2O3 films on sapphire 评估氮化铝插入层对蓝宝石上异质集成 Ga2O3 薄膜特性的影响

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-10-30 DOI: 10.1016/j.jcrysgro.2024.127977

Anfeng Wang , Ming-Qian Yuan , Yun-Duo Guo , Lin Gu , Yi Shen , Chengxi Ding , Xuejun Yan , Qing-Chun Zhang , Li Zhang , Xiao-Dong Zhang , Hong-Ping Ma

Integration of gallium oxide (Ga₂O₃) with highly thermal conductive AlN/sapphire substrate is more effective to dissipate heat in the Ga₂O₃-based devices. In this work, the properties of Ga₂O₃ films grown on sapphire and AlN/sapphire substrates via MOCVD were both examined via various experimental methods. The X-ray diffraction (XRD) analysis showed good crystallinity and different orientations of Ga₂O₃ and AlN thin films. The absorption properties and band gaps were extracted from UV/Vis spectra. The atomic force microscopy (AFM) scanning images showed smooth Ga₂O₃ surfaces on sapphire and AlN/sapphire substrates (RMSs of 2.4 nm and 4.8 nm, respectively). The scanning electron microscopy (SEM) highlighted well-defined grains of Ga₂O₃ and distinct boundaries of both heterostructures. X-ray photoelectron spectroscopy (XPS) analysis depicted the distributions of various components throughout the films. Finally, by using the time-domain thermoreflectance (TDTR) method, the thermal conductivity and the thermal boundary conductivity of Ga₂O₃ without AlN interlayer were found to be 3.1 W/(m·K) and 70.1 MW/(m²·K) respectively. By comparison, adding AlN interlayer made the thermal conductivity and thermal boundary conductivity rise to 3.3 W/(m·K) and 111.5 MW/(m²·K) respectively. These findings have demonstrated the high-quality Ga₂O₃/AlN integration and good heat dissipation provided by AlN interlayer, opening up new prospects for Ga₂O₃/AlN devices in the future.

将氧化镓（Ga2O3）与高导热的氮化铝/蓝宝石衬底结合在一起能更有效地为基于 Ga2O3 的器件散热。在这项工作中，通过各种实验方法，对通过 MOCVD 在蓝宝石和 AlN/蓝宝石衬底上生长的 Ga2O3 薄膜的特性进行了研究。X 射线衍射 (XRD) 分析表明 Ga2O3 和 AlN 薄膜具有良好的结晶性和不同的取向。从紫外/可见光谱中提取了吸收特性和带隙。原子力显微镜（AFM）扫描图像显示，蓝宝石和氮化铝/蓝宝石基底上的 Ga2O3 表面光滑（均方根误差分别为 2.4 nm 和 4.8 nm）。扫描电子显微镜（SEM）显示出两种异质结构的 Ga2O3 晶粒轮廓分明、边界清晰。X 射线光电子能谱（XPS）分析显示了薄膜中各种成分的分布。最后，通过使用时域热反射（TDTR）方法，发现无 AlN 中间膜的 Ga2O3 的热导率和热边界导率分别为 3.1 W/(m-K) 和 70.1 MW/(m2-K)。相比之下，添加 AlN 中间膜后，热导率和热边界导率分别上升到 3.3 W/(m-K) 和 111.5 MW/(m2-K)。这些研究结果表明，氮化铝中间膜实现了 Ga2O3/AlN 的高质量集成和良好散热，为未来的 Ga2O3/AlN 器件开辟了新的前景。

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引用次数: 0

High-pressure self-flux growth and characterization of Li-deficient Li0.95FeAs single crystals 缺锂 Li0.95FeAs 单晶的高压自流生长和表征

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-10-30 DOI: 10.1016/j.jcrysgro.2024.127981

N.D. Zhigadlo

Single crystals of LiFeAs were successfully grown by a self-flux method using the cubic anvil high-pressure and high-temperature technique. The reaction took place in a closed boron nitride crucible at a pressure of 1 GPa and a temperature of 1050 °C. The grown crystals, retrieved from solidified lump, exhibit plate-like shapes with sizes up to 0.7 × 0.7 × 0.15 mm³. Single-crystal x-ray diffraction refinement confirmed the high structural perfection of the grown crystals [space group P4/nmm, No 129, Z = 2, a = 3.77370(10) Å, c = 6.3468(6) Å, and V = 90.384(9) Å³] with the presence of a small deficiency on the Li site. The refined chemical composition of the produced crystals is Li_0.95FeAs. Temperature-dependent magnetization measurements revealed bulk superconductivity with a superconducting transition T_c = 16 K. A comparative analysis of LiFeAs, Li_1-_xFeAs, and Li_1-_yFe₁₊_yAs systems reveal that superconductivity is less sensitive to the Li deficiency, although it may completely disappear in the presence of both Fe excess and Li deficiency.

利用立方砧高压高温技术，通过自流式方法成功地生长出了锂铁砷单晶体。反应在封闭的氮化硼坩埚中进行，压力为 1 GPa，温度为 1050 ℃。从凝固的块状物中取出的生长晶体呈板状，大小可达 0.7 × 0.7 × 0.15 mm3。单晶 X 射线衍射细化证实了生长出的晶体具有高度完美的结构[空间群 P4/nmm，No 129，Z = 2，a = 3.77370(10) Å，c = 6.3468(6) Å，V = 90.384(9) Å3]，在锂位点上存在一个小的缺陷。所生成晶体的化学成分为 Li0.95FeAs。对 LiFeAs、Li1-xFeAs 和 Li1-yFe1+yAs 系统的比较分析表明，超导性对锂的缺失不太敏感，但在铁过剩和锂缺失的情况下，超导性可能会完全消失。

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引用次数: 0

Optical and scintillation properties of YAlO3:Ce scintillating single crystal fibers grown by laser heated pedestal growth method 激光加热基座生长法生长的 YAlO3:Ce 闪烁单晶光纤的光学和闪烁特性

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-10-29 DOI: 10.1016/j.jcrysgro.2024.127938

Yuke Ou , Xibin Wang , Xu Wu , Huamin Kou , Anhua Wu , Liangbi Su

Ce-doped yttrium aluminum perovskite (YAP:Ce) single crystal is recognized as modern, efficient scintillators with high light output, fast decay time, and emission peaks that match well with the receiving range of photomultiplier tubes. This makes it highly promising for applications in high energy physics, nuclear medicine, industrial detection and so on. In this work, 0.5 at% YAP:Ce scintillating crystals was successfully grown by a modified laser-heated pedestal growth (LHPG) method. The crystal exhibited a high light output of 13,754 ph./MeV, a short decay time constant of 28.62 ns, and a radioluminescence peak at 382 nm as shown in X-ray excited luminescence spectra.

掺杂铈的钇铝高闪石（YAP:Ce）单晶体是公认的现代高效闪烁体，具有光输出高、衰减时间快、发射峰与光电倍增管的接收范围相匹配等特点。因此，它在高能物理、核医学、工业检测等领域的应用前景十分广阔。在这项工作中，采用改进的激光加热基座生长（LHPG）方法成功地生长出了 0.5 at% 的 YAP:Ce 闪烁晶体。该晶体的光输出高达 13,754 ph./MeV，衰变时间常数短至 28.62 ns，并在 X 射线激发发光光谱中显示出 382 nm 处的辐射发光峰。

引用次数: 0

Growth of single crystalline GeSn alloy epilayer on Gd2O3/Si (111) engineered insulating substrate using RF sputtering and solid phase epitaxy 利用射频溅射和固相外延技术在 Gd2O3/Si (111) 工程绝缘衬底上生长单晶 GeSn 合金外延层

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-10-28 DOI: 10.1016/j.jcrysgro.2024.127972

Dushyant Singh , Tharundev V V , Subha Maity , Dhammapriy Gayakwad , H. Jörg Osten , Saurabh Lodha , Krista R Khiangte

The article showcases a low-cost, low-temperature deposition and HVM technique to develop single crystalline GeSn alloy epilayers on Gd₂O₃/Si (111) substrate. First, GeSn alloy amorphous layer is deposited on the insulating substrates using an Radio Frequency (RF) sputtering apparatus. Subsequently, an inductively coupled plasma-assisted chemical vapor deposition (ICP-CVD) process is used to deposit a SiO₂ capping layer to protect against Sn out-diffusion during heat treatment. The samples are then subjected to solid phase epitaxy (SPE) at 450 °C, 550 °C, and 650 °C. Sample processed for SPE at 450 °C has weak crystallinity and only shows Type-A stacking. Those processed for SPE at 550 °C and 650 °C, on the other hand, have revealed formation of the single-crystalline GeSn alloy epilayer with Type-A and Type-B stacking. However, SPE at 650 °C revealed tin out-diffusion and segregation effects. This work is significant for enabling the preparation of high-Sn-content GeSn alloy epilayers on insulating Gd₂O₃/Si (111) substrates, as it requires the initial deposition of a GeSn amorphous alloy epilayer using RF sputtering. This advancement promises benefits which includes advantages such as lower operating voltage, reduced leakage current, and minimized parasitic and short-channel effects, making it ideal for advancing RF technology.

文章展示了一种在 Gd2O3/Si (111) 基底上开发单晶 GeSn 合金外延层的低成本、低温沉积和 HVM 技术。首先，使用射频（RF）溅射设备在绝缘基底上沉积 GeSn 合金非晶层。随后，使用电感耦合等离子体辅助化学气相沉积（ICP-CVD）工艺沉积二氧化硅封盖层，以防止热处理过程中锡的外扩散。然后在 450 ℃、550 ℃ 和 650 ℃ 下对样品进行固相外延 (SPE)。在 450 ℃ 下进行 SPE 处理的样品结晶度较弱，只显示出 A 型堆叠。而在 550 ℃ 和 650 ℃ 下进行 SPE 处理的样品则形成了具有 A 型和 B 型堆叠的单晶 GeSn 合金外延层。然而，在 650 ℃ 下进行的 SPE 显示了锡的外扩散和偏析效应。这项工作对于在绝缘的 Gd2O3/Si (111) 基底上制备高锡含量的 GeSn 合金外延层具有重要意义，因为它需要使用射频溅射技术沉积 GeSn 非晶合金外延层。这项技术的优点包括工作电压更低、漏电流更小、寄生效应和短沟道效应最小等，因此是射频技术发展的理想选择。

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引用次数: 0

Simultaneous recovery of ammonium sulfate and ice from aqueous solution using eutectic freeze crystallization process 利用共晶冷冻结晶工艺从水溶液中同时回收硫酸铵和冰

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-10-28 DOI: 10.1016/j.jcrysgro.2024.127956

W.H.T. Ting , S.F. Salleh , N. Abdul Wahab , M.F. Atan , A.A. Abdul Raman , W.K. Ting , S.L. Kong , L.S. Lam , I.A.W. Tan

This study investigated the feasibility of eutectic freeze crystallization (EFC) process for ammonium sulfate (AS) salt recovery from 41 wt% AS solution. The EFC experiments were conducted using a 1 L double-jacketed crystallizer coupled with a recirculating chiller under varying freezing time, seed mass and seed size. The EFC process demonstrated successful AS salt recovery and water purification with the highest ice purity attained at 96.28 %. The construction of a binary AS-water phase diagram allowed the determination of the eutectic temperature, which was found to be −19.06 °C at 40 wt% of AS solution. The results indicated that the increase in freezing time enhanced the AS nucleation rate, growth rate, yield and mean product crystal size. The introduction of seeding not only provided well-controlled crystal nucleation and growth during EFC process, but also promoted the formation of larger, well-structured crystals and reduced agglomeration. Overall, the EFC process is a viable and promising option for recovering AS from wastewater, which offers high potential towards achieving zero liquid discharge goal, i.e. a sustainable and efficient approach in managing industrial effluent rich in ammonium and sulfate contaminants.

本研究调查了共晶冷冻结晶（EFC）工艺从 41 wt% AS 溶液中回收硫酸铵（AS）盐的可行性。EFC 实验是在不同的冷冻时间、种子质量和种子大小条件下，使用 1 升双层夹套结晶器和循环冷却器进行的。EFC 工艺成功实现了 AS 盐回收和水净化，冰纯度最高，达到 96.28%。通过构建二元 AS 水相图，可以确定共晶温度，在 AS 溶液重量为 40% 时，共晶温度为 -19.06 °C。结果表明，冷冻时间的延长提高了 AS 的成核率、生长率、产量和平均产品晶体尺寸。在 EFC 过程中，播种的引入不仅能很好地控制晶体的成核和生长，还能促进形成较大、结构良好的晶体并减少团聚。总之，EFC 工艺是一种从废水中回收 AS 的可行且前景广阔的方法，它为实现液体零排放目标提供了巨大的潜力，即一种管理富含铵和硫酸盐污染物的工业废水的可持续且高效的方法。

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引用次数: 0

Thermal conductivity of GaN with a vacancy and an oxygen point defect 具有空位和氧点缺陷的氮化镓的热导率

IF 1.7 4区材料科学 Q3 CRYSTALLOGRAPHY

Journal of Crystal Growth

Pub Date : 2024-10-28 DOI: 10.1016/j.jcrysgro.2024.127948

Takahiro Kawamura , Ryogo Nishiyama , Toru Akiyama , Shigeyoshi Usami , Masayuki Imanishi , Yusuke Mori , Masashi Yoshimura

GaN has high thermal conductivity, therefore it is expected to be used in high-power, high-frequency, and compact electronic devices. However, GaN includes many defects and impurities, which reduce its thermal conductivity. Therefore, the effect of defects and impurities on the thermal conductivity of GaN needs to be understood for optimal thermal management. In this study, the thermal conductivity of GaN in three cases – with a Ga vacancy, an N vacancy, and an O impurity substituted at an N site – was investigated using first-principles calculations. Thermal conductivity was calculated based on the Boltzmann transportation equation under the relaxation time approximation. At 300 K, the thermal conductivity values of pure GaN and GaN with a Ga vacancy, an N vacancy, and an O substitutional impurity (defect concentrations

\sim 1.3 \times 10

²¹ cm⁻³) were 325, 74, 70, and 138 W/(m K), respectively. It was found from the spectrum of thermal conductivity that acoustic phonons at frequencies lower than 10 THz were responsible for most of the thermal conductivity of GaN. We also examined the effect of sample size on thermal conductivity and found that the cumulative thermal conductivity value of pure GaN was less than 9% of the bulk value, when the sample size was smaller than 100 nm.

氮化镓具有高热导率，因此有望用于大功率、高频率和紧凑型电子设备。然而，氮化镓含有许多缺陷和杂质，会降低其热导率。因此，需要了解缺陷和杂质对氮化镓热导率的影响，以优化热管理。在本研究中，我们利用第一性原理计算研究了 GaN 在三种情况下的热导率：Ga 空位、N 空位和在 N 位点上被 O 杂质取代。热导率的计算基于弛豫时间近似下的玻尔兹曼输运方程。在 300 K 下，纯 GaN 和含有 Ga 空位、N 空位和 O 置换杂质（缺陷浓度∼1.3×1021 cm-3）的 GaN 的热导率值分别为 325、74、70 和 138 W/（m K）。从热导率频谱中发现，频率低于 10 太赫兹的声子是 GaN 热导率的主要原因。我们还研究了样品尺寸对热导率的影响，发现当样品尺寸小于 100 nm 时，纯氮化镓的累积热导率值不到块体值的 9%。

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引用次数: 0