Modulation-doped growth of mosaic graphenewith single-crystalline p–n junctionsfor efficient photocurrent generation

摘要

Device applications of graphene such as ultrafast transistors and photodetectors benefit fromthe combination of both high-quality p- and n-doped components prepared in a large-scalemanner with spatial control and seamless connection. Here we develop a well-controlledchemical vapour deposition process for direct growth of mosaic graphene. Mosaic grapheneis produced in large-area monolayers with spatially modulated, stable and uniform doping,and shows considerably high room temperature carrier mobility of B5,000 cm~2 V~(-1) s~(-1)inintrinsic portion and B2,500 cm~2V~(-1)s~(-1)in nitrogen-doped portion. The unchanged crystalline registry during modulation doping indicates the single-crystalline nature of p–n junctions. Efficient hot carrier-assisted photocurrent was generated by laser excitation at thejunction under ambient conditions. This study provides a facile avenue for large-scalesynthesis of single-crystalline graphene p–n junctions, allowing for batch fabrication andintegration of high-efficiency optoelectronic and electronic devices within the atomically thinfilm.