Single-walled carbon nanotubes (SWCNTs) have many applications, including high speed transistor devices (see Figure 1). SWCNTs are grown on single-crystal quartz wafers and then transferred onto silicon wafers by a process that involves gold evaporation and thermal release tape. When they are grown, there are usually between 4 to 10 SWCNTs per micrometer on the surface of the quartz wafer. Increasing the number of SWCNTs per micrometer increases the electrical performance of transistor devices linearly . In this project, we attempt to perform multiple transfers of SWCNTs onto the same wafer in order to increase their density. One of the problems we face is that residue from the initial transfer is preventing any additional transfers from succeeding. We approach this quandary using two different techniques: applying different adhesives and using various chemical solutions to clean any tape residue that may affect the transfer process. We use scanning electron microscopy (SEM) to detect any improvement in surface cleanliness and observe the damage, if any, done to the SWCNTs by our process using probing equipment to measure I-V characteristics and performance. From our results we were able to show that multiple transfers did indeed improve performance even though the multiple transfers were not 100% successful.
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