Gate-Defined Accumulation-Mode Quantum Dots in Monolayer and Bilayer WSe2

We report the fabrication and characterization of gate-defined hole quantum dots in monolayer and bilayer WSe2. The devices are operated with gates above and below the WSe2 layer to accumulate a hole gas, which for some devices is then selectively depleted to define the dot. Temperature dependence of conductance in the Coulomb-blockade regime is consistent with transport through a single level, and excited-state transport through the dots is observed at temperatures up to 10 K. For adjacent charge states of a bilayer-WSe2 dot, the magnetic field dependence of excited-state energies is used to estimate g factors between 0.8 and 2.4 for different states. These devices provide a platform to evaluate valley-spin states in monolayer and bilayer WSe2 for application as qubits.