  A van der Waals (vdW) charge qubit, electrostatically confined within
two-dimensional (2D) vdW materials, is proposed as building block of future
quantum computers. Its characteristics are systematically evaluated with
respect to its two-level anti-crossing energy difference ($\Delta$). Bilayer
graphene ($\Delta$ $\approx$ 0) and a vdW heterostructure ($\Delta$ $\gg$ 0)
are used as representative examples. Their tunable electronic properties with
an external electric field define the state of the charge qubit. By combining
density functional theory and quantum transport calculations, we highlight the
optimal qubit operation conditions based on charge stability and energy-level
diagrams. Moreover, a single-electron transistor (SET) design based on trilayer
vdW heterostructures capacitively coupled to the charge qubit is introduced as
measurement setup with low decoherence and improved measurement properties. It
is found that a $\Delta$ greater than 20 meV results in a rapid mixing of the
qubit states, which leads to a lower measurement quantity, i.e. contrast and
conductance. With properly optimized designs, qubit architectures relying on 2D
vdW structures could be integrated into an all-electronic quantum computing
platform.
