Ammonothermal cubic boron nitride single crystal growth near ambient pressure and temperature

接近环境压力和温度的氨热立方氮化硼单晶生长

• 批准号: 1832824
• 负责人: Siddha Pimputkar
• 金额: $ 59.3万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1832824&HistoricalAwards=false
• 关键词: Ammonothermal; cubic; boron; nitride; single

NON-TECHNICAL DESCRIPTION: Boron nitride is a semiconductor material, and in its cubic crystal structure, it is one of the hardest materials known. Unlike diamond, boron nitride can be used in more reactive environments given its superior stability against oxidation and unintended chemical reactions with, for example, iron at elevated temperatures. Synthesis of large diameter single crystals would significantly advance high-pressure experimental configurations when used as anvils, and the power electronics field by achieving high-efficiency electrical power conversion. Availability of large single crystals would be transformative to multiple additional areas by enabling wide-scale research using high-quality material and permitting exploration of novel electronic devices. Current methods used to synthesize this material yield only small crystals at high cost making them impractical for wide-scale adaption. This project investigates growth of single crystal boron nitride using a different, more scalable technique which operates under milder conditions. The PI and co-PI are devoted to education and accordingly, their research results are being incorporated into graduate courses. The PI is hosting wiki articles and videos on a world-accessible server by working closely with student volunteers. Additionally, the PI is visiting regional, underrepresented and rural, high schools to educate the public on the impact of materials on society. The co-PI is an advocate for underrepresented groups and is continuing his participation in Open Houses and similar events.TECHNICAL DETAILS: Cubic boron nitride (c-BN) is a wide bandgap semiconductor and one of the hardest materials known. Synthesis of this materials is currently limited to high-pressure anvil systems limiting their size to ~1 mm in diameter. The ammonothermal method, utilizing supercritical ammonia at pressures below 300 MPa and temperatures below 800 C, is a solution-based, bulk single crystal growth technique which is being explored to enable growth of large single crystal c-BN. Solubility of BN in a variety of solutions utilizing alkali and alkali-earth metals and halides as mineralizers is under investigation. Suitable growth conditions are applied to bulk, single crystal growth of c-BN on c-BN seeds synthesized as part of this research in anvil systems. BN crystals are characterized for their properties and tied to growth conditions. Availability of large, single crystal c-BN would prove transformative for power electronics research in the form of substrates given its highly beneficial physical properties (high thermal conductivity and breakdown voltages) and the ability to be doped both p- and n-type. Similarly, large single crystal material would have a profound impact on the fabrication of super-hard ceramic tools. This research provides in-depth education for students on the topic of single crystal growth methods and associated (novel) equipment development reinvigorating the waning single crystal growth community.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

非技术描述：氮化硼是一种半导体材料，在其立方晶体结构中，它是已知最硬的材料之一。与金刚石不同，氮化硼可用于反应性更强的环境中，因为它具有优异的抗氧化和在高温下与例如铁发生意外化学反应的上级稳定性。大直径单晶的合成将显着推进高压实验配置时，作为砧，并通过实现高效率的电力转换的电力电子领域。大单晶的可用性将通过使用高质量材料进行大规模研究并允许探索新的电子设备来改变多个其他领域。目前用于合成这种材料的方法仅以高成本产生小晶体，使得它们不适合大规模应用。该项目研究使用不同的，更可扩展的技术，在温和的条件下操作的单晶氮化硼的生长。PI和co-PI致力于教育，因此，他们的研究成果被纳入研究生课程。PI通过与学生志愿者密切合作，在全球可访问的服务器上托管wiki文章和视频。此外，PI正在访问代表性不足的地区和农村高中，以教育公众了解材料对社会的影响。共同PI是一个倡导者，为代表性不足的群体，并继续参加开放日和类似的活动。技术专长：立方氮化硼（c-BN）是一种宽带隙半导体和已知的最硬的材料之一。这种材料的合成目前仅限于高压砧系统，将其尺寸限制在直径约1 mm。在低于300 MPa的压力和低于800 ℃的温度下利用超临界氨的氨法是一种基于溶液的块状单晶生长技术，其正在被探索以能够生长大单晶c-BN。BN在利用碱金属和碱土金属以及卤化物作为矿化剂的各种溶液中的溶解度正在研究中。合适的生长条件被施加到块体，单晶生长的c-BN的c-BN种子合成作为本研究的一部分，在砧系统。BN晶体的特征在于它们的性质并与生长条件有关。大单晶c-BN的可用性将被证明是以衬底形式进行电力电子研究的变革，因为其具有非常有益的物理特性（高导热性和击穿电压）以及p型和n型掺杂的能力。同样，大单晶材料将对超硬陶瓷刀具的制造产生深远的影响。这项研究为学生提供了关于单晶生长方法和相关（新）设备开发的深入教育，以重振日益衰落的单晶生长社区。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

On the solubility of boron nitride in supercritical ammonia-sodium solutions

• DOI: 10.1016/j.jcrysgro.2023.127381
• 发表时间: 2023-08-02
• 期刊: JOURNAL OF CRYSTAL GROWTH
• 影响因子: 1.8
• 作者: Dooley，Jacob;Stoddard，Nathan;Pimputkar，Siddha
• 通讯作者: Pimputkar，Siddha