A semiconductor structure includes stack structures. Each of the stack structures comprises a first conductive material, a chalcogenide material over the first conductive material, a second conductive material over the chalcogenide material, and a first dielectric material between the chalcogenide material and the first conductive material and between the chalcogenide material and the second conductive material. The semiconductor structure further comprises a second dielectric material on at least sidewalls of the chalcogenide material. The chalcogenide material may be substantially encapsulated by one or more dielectric materials. Related semiconductor structures and related methods are disclosed.