  Group-IV color centers in diamond have attracted significant attention as
solid-state spin qubits because of their excellent optical and spin properties.
Among these color centers, the tin-vacancy (SnV$^{\,\textrm{-}}$) center is of
particular interest because its large ground-state splitting enables long spin
coherence times at temperatures above 1$\,$K. However, color centers typically
suffer from inhomogeneous broadening, which can be exacerbated by
nanofabrication-induced strain, hindering the implementation of quantum nodes
emitting indistinguishable photons. Although strain and Raman tuning have been
investigated as promising techniques to overcome the spectral mismatch between
distinct group-IV color centers, other approaches need to be explored to find
methods that can offer more localized control without sacrificing emission
intensity. Here, we study electrical tuning of SnV$^{\,\textrm{-}}$ centers in
diamond via the direct-current Stark effect. We demonstrate a tuning range
beyond 1.7$\,$GHz. We observe both quadratic and linear dependence on the
applied electric field. We also confirm that the tuning effect we observe is a
result of the applied electric field and is distinct from thermal tuning due to
Joule heating. Stark tuning is a promising avenue toward overcoming detunings
between emitters and enabling the realization of multiple identical quantum
nodes.
