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).