Centre of Excellence in Nanoelectronics, IIT Bombay, Mumbai 400076, Maharashtra, India.
ACS Appl Mater Interfaces. 2012 Mar;4(3):1434-9. doi: 10.1021/am201691s. Epub 2012 Feb 28.
We report a unipolar operation in reduced graphene oxide (RGO) field-effect transistors (FETs) via modification of the source/drain (S/D) electrode interfaces with self-assembled monolayers (SAMs) of 5-(4-hydroxyphenyl)-10,15,20-tri-(p-tolyl) zinc(II) porphyrin (Zn(II)TTPOH) molecules. The dipolar Zn(II)TTPOH molecules at the RGO/platinum (Pt) S/D interface results in an increase of the electron injection barrier and a reduction of the hole-injection barrier. Using dipole measurements from Kelvin probe force microscopy and highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) calculations from cyclic voltammetry, the electron and hole injection barriers were calculated to be 2.2 and 0.11 eV, respectively, indicating a higher barrier for electrons, compared to that of holes. A reduced gate modulation in the electron accumulation regime in RGO devices with SAM shows that unipolar RGO FETs can be attained using a low-cost, solution-processable fabrication technique.
我们通过用自组装单层（SAM）修饰源/漏（S/D）电极界面，在还原氧化石墨烯（RGO）场效应晶体管（FET）中实现了单极性操作，SAM 由 5-（4-羟苯基）-10,15,20-三-（对甲苯基）锌（II）卟啉（Zn（II）TTPOH）分子组成。RGO/铂（Pt）S/D 界面上的偶极 Zn（II）TTPOH 分子导致电子注入势垒增加，空穴注入势垒降低。使用来自 Kelvin 探针力显微镜的偶极测量和来自循环伏安法的最高占据分子轨道-最低未占据分子轨道（HOMO-LUMO）计算，分别计算出电子和空穴注入势垒为 2.2 和 0.11 eV，表明电子势垒比空穴势垒更高。在具有 SAM 的 RGO 器件中，电子积累区的栅极调制降低表明，可以使用低成本、溶液处理的制造技术获得单极性 RGO FET。
