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Graphene-based Novel Micro/nano Devices

Posted on:2016-11-07Degree:DoctorType:Dissertation
Country:ChinaCandidate:H TianFull Text:PDF
GTID:1108330503456164Subject:Electronic Science and Technology
Abstract/Summary:PDF Full Text Request
As Moore’s law continues, the dimension of semiconductor devices keeps scaling down, and the technology node of microelectronics is already down to 14 nm. However the mobility of the silicon will significantly decrease with the decreasing of the thickness. Graphene, a representative 2D materials which shows ultra-high mobility with only one-atom thickness, is quite promising for the development of ―More Moore‖. In addition, the superior mechanical, thermal, optical and electrical properties of graphene made it great potential to breakthrough in ―More than Moore‖. Therefore, the graphene-based novel micro/nano devices, which are systematically shown on the materials preparation, device performance, physical mechanism and device integration, are focused in this thesis. A series of novel graphene devices have been obtained such as transistor, memory, sound source, mechanical sensor, light emitting device, thermal rectifier and etc., which could expand the research space of graphene devices and lay foundation for the next generation micro/nano devices.First, graphene growth and patterning are investigated. Direct growth graphene on insulating substrate is developed and graphene microribbon with high mobility is obtained. The shape of the suspended graphene could be tuned by lasing irradiation. Meanwhile, a laser scribing technology is proposed to direct growth and pattering graphene in one-step. This method could be regarded as a platform to develop and integrate numerous graphene devices.Second, novel graphene-based transistor and memory are developed. Graphene-MoS2 heterojunction is proposed with the combined advantages of high mobility graphene and bandgap of MoS2, leading to the high mobility and large on/off ratio in the transistor. And to decrease the EOT could break the limitation of the sub-threshold swing perspectively. The graphene is also inserted into RRAM, which could decrease the power significantly and show the evidence of the oxygen ion movement in RRAM. The laser-scribed graphene could enable RRAM with Fin-like structure, which has the benefit of low-voltage operation and flexibility. A concept of gate controlled RRAM is proposed by the combination of the bilayer graphene and the gate terminal, which could enable the function of in-situ tuning the switching window.Third, novel graphene-based sensors and actuators are designed. Transparent and flexible graphene sound source is fabricated with the flat sound response in wide frequency range. A novel graphene earphone is also demonstrated. High sensitivity graphene strain and pressure sensors are realized and energy harvesting is presented. A giant piezoelectric effect is also observed in graphene. Its piezoelectric coefficient is two orders higher than traditional piezoelectric materials. The electroluminescence is observed in graphene and the light wavelength could be tuned by the gate voltage. Graphene thermal rectifier could be realized by utilizing phonon transport in a asymmetric structure.Finally, the integration method of graphene-based devices are studied. A design method is built to convert photo mask into laser patterns. Wafer-scale, high-performance and low-cost graphene transistors, photodetectors and loudspeaker, which could promote the practical applications of graphene micro/nano devices.
Keywords/Search Tags:graphene, novel micro/nano device, materials preparation, patterning, on-chip integration
PDF Full Text Request
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