EAGER: Lateral Heterojunctions: Fabrication & Characteristics of a Novel Concept in 2D Materials Electronics

非技术描述：诸如石墨烯和二硫化钼的二维材料已经吸引了相当大的关注，因为它们可以提供在小型化的极限（即，基于一种惰性的、稳定的原子层，只有一层厚。在此框架内，EAGER研究项目旨在开发不同单层材料之间横向连续过渡的概念，其中材料的成分通过化学手段控制以快速过渡，例如，从二硫化钼到二硒化钼最终目标是开发一种程序，通过这种程序，材料成分和随后的电子特性的明确定义的模式可以“编织”成一个单一的原子片，就像格子布上的图案一样。如果成功的话，这种方法将提供比传统方法明显更容易的器件结构制造。该项目是在西班牙裔服务机构进行，并直接受益于多个西班牙裔本科生和研究生在实验室。它与本科生的研究经验网站由主要investigator.Technical描述：本项目旨在开发的方法，用于制备横向组成的异质结过渡金属二硫属化物单层膜，利用改进的化学气相沉积方法。它建立在主要研究者实验室的发现基础上，该实验室允许制备任何成分的二硫化钼和二硒化钼之间的合金。初步数据表明，成分梯度的meV/微米尺度上可以制造。这个研究项目调查这些梯度是否可以足够尖锐和控制，以便他们可以建立量子威尔斯或其他功能元件的单层设备。为此，研究人员在薄膜生长期间和通过硫-硒交换对薄膜进行生长后处理期间应用硫族元素注入的专用控制。表征主要通过光学光谱法进行，并辅以电气测试，取得了令人鼓舞的结果。如果该项目取得成功，所产生的结构将允许将当前GaAs/GaAlAs异质结技术的许多材料和器件概念转移到二维薄膜的世界，该异质结技术是许多现代光电子学的基础。

Non-technical Description: Two-dimensional materials such as graphene and molybdenum disulfide have attracted considerable attention because they may offer a facile way of fabricating electronic devices at the ultimate limit of miniaturization, i.e., based on an inert, stable atomic sheet that is only a single layer thick. Within this framework, this EAGER research project intends to develop the concept of lateral continuous transitions between different single-layer materials, in which the composition of the material is controlled by chemical means to transition rapidly, e.g., from molybdenum disulfide to molybdenum diselenide. The ultimate goal is to develop a procedure by which well-defined patterns of material composition and ensuing electronic properties can be "woven" into a single atomic sheet like a pattern in a plaid cloth. If successful, this approach will provide for significantly more facile fabrication of device structures than the conventional approach. This project is conducted at a Hispanic Serving institution and directly benefits multiple Hispanic undergraduate and graduate students in the lab. It synergizes with a Research Experience for Undergraduate students site directed by the principle investigator.Technical Description: This project intends the development of methods for the preparation of lateral compositional heterojunctions in transition metal dichalcogenide single-layer films utilizing a modified chemical vapor deposition approach. It builds on findings in the principle investigator's lab that permit the preparation of alloys between molybdenum disulfide and molybdenum diselenide at any composition. Preliminary data show that compositional gradients on the meV/micrometer scale can be fabricated. This research project investigates whether these gradients can be made sufficiently sharp and controlled so that they can set up quantum wells or other functional elements for single-layer devices. To this end, researchers apply both dedicated control of the chalcogen injection during the film growth and post-growth processing of films by sulfur-selenium exchange. Characterization proceeds primarily by optical spectroscopy augmented by electrical testing where promising results are achieved. If the project has success, the resultant structures will permit transfer of many materials and device concepts of current GaAs/GaAlAs heterojunction technology, which is the base of much of modern optoelectronics, to the world of two-dimensional films.