High-voltage carrier transport measurements in graphene and MoS₂

Pulsed current–voltage characteristics have been measured for CVD monolayer graphene and exfoliated MoS₂ on HfO₂ and Al₂O₃ (sapphire) under controlled lattice temperature conditions. The unintentional donor density in MoS₂ is 3.6 × 10¹¹cm⁻³ and hole density in graphene is 1.4 × 10¹² cm⁻³. Graphene samples withstand 47 V bias when 10 ns electric pulses are applied and 131 V when 3 ns pulses are used. MoS₂ samples suffer from thermal breakdown at 22 V on sapphire and 145 V on HfO₂ upon application of 10 ns and 3 ns duration electrical pulses, respectively. The results are treated in terms of electron drift velocity estimated from the data on current and constant carrier density under the assumption of uniform electric field. The highest hole velocity of ∼1.8(3.1)×10⁷ cm/s is estimated in graphene on sapphire(HfO₂).