Abstract

Next generation electronic devices are likely to rely on quantum technologies. Spintronics is one such emergent technology, which uses electron spin to store information [1,2]. Spintronics offers faster processing times than conventional alternatives as well as nonvolatile magnetic memory. It is attractive think of using graphene for this application because of the long spin lifetime and spin propagation length at room temperature. However, its spin orbit interaction (SOI) is naturally very low, making it impossible to practically create spintronic devices. 
 The properties of graphene can be artificially engineered by stacking other ultra-thin materials above or below in what are known as van der Waals heterostructures [3]. This method is very useful in effectively creating customized materials. It is theoretically predicted that the SOI in graphene is enhanced by placing in contact with topologically insulating materials such Bi2Se3 [4,5]. We create van der Waals heterostructures of graphene with Bi2Se3 and investigate layer sequences and fabrication process which limit device yield. We use a dry transfer process create devices, a technique that ensures high quality connecting interfaces by avoiding contamination from processing materials. This is paramount to fabricating high quality devices and preserving the transport properties of graphene. 

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⁵ L. Kou et al., Nano Lett. 13, 6251 (2013).