In this work, suspended 4-mm-wide graphene membranes are obtained through a sublimation-assisted transfer process, using few-layer films grown by microwave plasma chemical vapor deposition. This result is achieved by a new approach involving the removal of the graphene-transfer supporting layer in vacuum. The membranes produced by this procedure show the largest area-to-thickness ratio described in the literature with a 2-fold improvement when compared to the best results using the conventional PMMA-assisted transfer, and a five orders of magnitude increase when compared to previous sublimation-assisted processes. This breakthrough allows the implementation of a wide variety of technological applications where 2D materials with atomic thickness and large areas are required. As large-area free-standing membranes are difficult to obtain, a new figure of merit is defined to benchmark the various methods of suspending graphene. A high transfer yield is achieved, and the mechanical and optical properties of the 3.7 nm thick membranes are evaluated. Finally, a prototype condenser microphone is built and tested, and found to exhibit an enhanced specific response.

在这项工作中，通过升华辅助转移过程，使用通过微波等离子体化学气相沉积法生长的几层薄膜，获得了悬浮的4毫米宽的石墨烯膜。通过涉及在真空中去除石墨烯转移支撑层的新方法来获得该结果。通过这种方法生产的膜显示出文献中描述的最大的膜厚比，与使用传统的PMMA辅助转移的最佳结果相比，提高了2倍，与以前的膜相比，提高了五个数量级升华辅助过程。这一突破使得可以实现需要原子厚度和大面积2D材料的各种技术应用。由于很难获得大面积的自支撑膜，定义了新的品质因数，以对各种悬浮石墨烯的方法进行基准测试。实现了高转移收率，并评估了3.7 nm厚膜的机械和光学性能。最终，构建并测试了原型电容式麦克风，发现该麦克风表现出增强的特定响应。