  We analyze the coupling of two qubits via an epitaxial semiconducting
junction. In particular, we consider three configurations that include pairs of
transmons or gatemons as well as gatemon-like two qubits formed by an epitaxial
four-terminal junction. These three configurations provide an electrical
control of the interaction between the qubits by applying voltage to a metallic
gate near the semiconductor junction and can be utilized to naturally realize a
controlled-Z gate (CZ). We calculate the fidelity and timing for such CZ gate.
We demonstrate that in the absence of decoherence, the CZ gate can be performed
under $50\ {\rm ns}$ with gate error below $10^{-4}$.
