Sharma Intu, Batra Yogita, Flauraud V, Brugger Jürgen, Mehta Bodh Raj
Thin Film Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi, 110016, India.
Microsystems Laboratory, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland.
J Nanosci Nanotechnol. 2018 Mar 1;18(3):1824-1832. doi: 10.1166/jnn.2018.14265.
The growth of MoS2 layers of desired dimensions at predefined locations is essential for fabricating opto-electronic devices based solely on MoS2 or on hetero-structures based on MoS2. Here we present a new route for patterned growth of MoS2 by combining radio frequency (RF) magnetron sputtering, stencil mask lithography and vapour phase sulfurization. The present method does not involve chemical etchants and organic photoresist and hence provides a simplified process of achieving MoS2 patterns. Here, the control over the number of layers (mono, few and bulk) of MoS2 is achieved by varying the thickness of Mo films. The statistical variation in thickness i.e., number of MoS2 layers within the individual patterns is investigated from Raman mappings which revealed the uniform growth of 3-4 MoS2 layers. From Kelvin probe force microscopy, the surface potential values of MoS2 patterns lie in the range -350 to -370 mV, which is consistent with 2D MoS2 layer with thickness of 3-4 layers. The surface potential analysis across individual patterns indicates weakly n-type doping of few layers MoS2 with Fermi level located ~0.83-0.85 eV below the conduction band edge.
在预定义位置生长具有所需尺寸的二硫化钼（MoS2）层对于制造仅基于MoS2或基于MoS2的异质结构的光电器件至关重要。在此，我们提出了一种通过结合射频（RF）磁控溅射、模板掩膜光刻和气相硫化来实现MoS2图案化生长的新途径。本方法不涉及化学蚀刻剂和有机光刻胶，因此提供了一种实现MoS2图案的简化工艺。在此，通过改变钼（Mo）膜的厚度来控制MoS2的层数（单层、少数层和体相）。从拉曼映射研究了单个图案内厚度的统计变化，即MoS2层数，结果表明3 - 4层MoS2生长均匀。通过开尔文探针力显微镜，MoS2图案的表面电势值在-350至-370 mV范围内，这与厚度为3 - 4层的二维MoS2层一致。对单个图案的表面电势分析表明，少数层MoS2具有弱n型掺杂，费米能级位于导带边缘以下约0.83 - 0.85 eV处。
