2D Materials on Compound Semiconductors

原子薄，固有的2D半导体为超低功耗应用提供了具有优异光响应的纳米级器件。利用脱落的微片，器件和简单集成电路已被报道，支持纳米光电子学的潜在应用。探索新的设备功能以及材料的放大是下一个挑战；直到最近，研究人员才开始解决将这些材料集成到化合物半导体（CS）平台中的问题。全世界只有不到20个实验室配备了使用分子束外延（MBE）或原子层沉积（ALD）“生长”单层二维材料的设备。能够解决2D/CS混合异质结构的能力明显不足，这为学术探索和工业开发提供了机会。因此，新成立的卡迪夫MBE设施，由牛津ALD支持的设备齐全的Ser-Cymru实验室为这个CASE学生提供了一个国际独特的环境。项目目标和方法：该学生将开发、分析和模拟一系列选定的二维材料（MoS2、WS2和WSe2），并将其集成到光电应用的GaN平台中。她/他将学习/开发新的方法，包括使用ALD (Oxford)，简单剥离/转移方法（Cardiff）以及由2D/(InAl)GaN合金（MBE）组成的杂化异质结构，并注意到MoS2与In0.15Ga0.85N的晶格匹配。对这些异质结构的分析包括晶片尺度的x射线衍射、光致发光、时间分辨光致发光和拉曼光谱，并辅以能带结构模拟。该学生还将在PHYSX-CMP和ENGIN材料网络中探索免费表征方法和合作的机会。科学成就和成果：通过ALD在III-V系统上生产高结晶2D层的挑战有望带来科学突破，包括在中等工艺温度下的单层2D晶体，以及对2D/III-N合金、界面和异质结构的底层物理控制。预期结果包括适合未来扩大规模的演示和分析，从而导致卡迪夫-牛津大学继续合作，如EPSRC“冒险制造”提案（正在投标）。

Atomically-thin, inherently 2D semiconductors offer nano-scale devices with excellent response to light for ultra-low-power applications. Using exfoliated microflakes, devices and simple integrated circuits have been reported, underpinning potential applications in nano-optoelectronics. Exploring new device functionality along with materials scale-up are the next challenges; only recently have researchers started to address the integration of these materials into the compound semiconductor (CS) platform. Fewer than twenty labs world-wide are equipped to "grow" single-monolayer 2D materials using molecular beam epitaxy (MBE) or atomic layer deposition (ALD). Significantly fewer have the ability to address the hybrid 2D/CS heterostructure which provides an opportunity for academic exploration and industrial exploitation. Thus, the newly-established Cardiff MBE facility, the well-equipped Ser-Cymru Laboratory supported by Oxford ALD provide an internationally unique setting for this CASE Studentship.Project aims and methods: This student will develop, analyse and simulate a select family of 2D materials (MoS2, WS2 and WSe2) integrated into the GaN platform for optoelectronic applications. She/he will learn/develop new methods to include 2D deposition using both ALD (Oxford), simple exfoliation/transfer methods (Cardiff) along with hybrid heterostructures comprised of 2D/(InAl)GaN alloys (MBE) noting that MoS2 is lattice-matched to In0.15Ga0.85N. Analysis of these new heterostructures includes research-to-wafer-scale xray diffraction, photoluminescence, time-resolved-photoluminescence along with Raman, and supported by band structure simulation. The student will also explore opportunities within PHYSX-CMP and ENGIN Materials Network for complimentary characterization methods and collaborations. Scientific excellence and outcomes: The challenge of producing highly-crystalline 2D layers via ALD on III-V systems is expected to result in scientific breakthroughs including single-monolayer 2D crystals at moderate process temperatures followed by control of the underlying physics in 2D/III-N alloys, interfaces and heterostructures. Anticipated outcomes include the demonstration and analysis appropriate for future scale-up leading to continued Cardiff-Oxford collaborations such as the EPSRC "Adventurous Manufacturing" Proposal (bid-in-progress).