Enhanced Negative Photoconductivity in InAs Nanowire Phototransistors Surface‐Modified with Molecular Monolayers

• DOI: 10.1002/admi.201701104
• Publication Date: 2017-12-11T07:33:00Z
• Authors: Lifan Shen; SenPo Yip; Changyong Lan; Lei Shu; Dapan Li; Ziyao Zhou; Chun‐Yuen Wong; Edwin Y. B. Pun; Johnny C. Ho
• Keywords: Photoexcitation; Photoconductivity

Abstract Negative photoconductivity (NPC) mechanisms are widely investigated for high‐performance InAs nanowire (NW) phototransistors, where these usually attributed to severe carrier scattering centers, light‐assisted hot electron trapping in the surface oxide, and/or defects induced photogating layer. However, further insights into their photodetecting mechanisms, as well corresponding performance enhancement of NW still very limited. This work reports NPC behavior surface‐modified phototransistors based on photoexcitation majority bonded sulfur monolayer under optical illumination. In order enhance ability layer, aromatic thiolate (ArS − )‐based molecular with strong electron‐withdrawing group is employed using simple wet chemistry modification phototransistors. The magnitude increased by stronger ArS ‐based monolayer, enabling electrons be trapped and released more efficiently, resulting good sensitivity, fast photoresponse, long‐term stability low intensity visible light. These results confirm potential surface‐passivated monolayers application realization high‐sensitive stable room temperature nanoscale photodetectors.