Remote modulation doping in van der Waals heterostructure transistors

摘要

Carriers in a molybdenum disulfide transistor can be modulated without decreasing mobility by remote doping and charge transfer through a van der Waals heterostructure, which avoids dopant-induced impurity scattering in the channel.Doping is required to modulate the electrical properties of semiconductors but introduces impurities that lead to Coulomb scattering, which hampers charge transport. Such scattering is a particular issue in two-dimensional semiconductors because charged impurities are in close proximity to the atomically thin channel. Here we report the remote modulation doping of a two-dimensional transistor that consists of a band-modulated tungsten diselenide/hexagonal boron nitride/molybdenum disulfide heterostructure. The underlying molybdenum disulfide channel is remotely doped via controlled charge transfer from dopants on the tungsten diselenide surface. The modulation-doped device exhibits two-dimensional-confined charge transport and the suppression of impurity scattering, shown by increasing mobility with decreasing temperature. Our molybdenum disulfide modulation-doped field-effect transistors exhibit a room-temperature mobility of 60 cm(2) V-1 s(-)(1); in comparison, transistors that have been directly doped exhibit a mobility of 35 cm(2) V-1 s(-)(1).