石墨烯转移工艺对石墨烯传感器检测汞离子的影响

本工作采用化学气相沉积法(CVD)石墨烯制备场效应晶体管(FET)传感器，在石墨烯表面修饰DNA，用于检测汞离子.为探索转移方法对石墨烯传感器件性能的影响，制备了3种不同转移工艺的石墨烯样品，分别是PMMA转移方法中退火烧除PMMA的石墨烯、用丙酮洗去PMMA的石墨烯和Au转移的石墨烯，对石墨烯样品进行拉曼光谱、分光光度计、光学显微镜(OM)、扫描探针显微镜(SPM)的表征.通过FET转移特性曲线的输出，得到汞离子对石墨烯掺杂情况的变化，从而考察了各种石墨烯传感器对汞离子的检测性能.结果表明，Au转移的石墨烯表面清洁程度最佳，SPM图像显示其表面平坦无杂质，表面粗糙度(Ra)仅为0.45 nm.用该种石墨烯制备的传感器件对汞离子检测的检测限达10 pM，且FET的狄拉克点变化也最大，达-0.132 V.
In this work, chemical vapor deposition (CVD) graphene was decorated with DNA to fabricate field effect transistor (FET) sensors for mercury ion detection. To figure out the effects of different samples on the detection of Hg2+, this study exploited three different samples:the sample on which PMMA was burned, the sample on which PMMA was washed by acetone and the sample which was transferred by Au. The quality of the graphene was characterized by Raman spectroscopy, spectrophotometer, optical microscope as well as scanning probe microscopy. Three different devices were fabricated by corresponding samples.Through the FET transfer curves, different doping conditions of graphene were obtained, and the detetion performance of various graphene sensors was investigated. It was shown that the sample which was transferred by Au had the cleanest surface. In the corresponding device, the detection limit of Hg2+ could achieve 10 pM, and the change of Dirac point was the largest which was up to -0.132 V.