We investigated the structural and sub-structural characteristics of ZnO films obtained by chemical bath deposition from solutions of zinc sulfate, thiourea, and ammonia. The duration of deposition ranged from 20- to 120-minutes. The concentration of thiourea was varied from 0.1- to 3-mol. We detailed the structural and sub-structural characteristics of these films using high-resolution scanning electron microscopy and x-ray diffraction. This research enables us to study features of the films’ structural formation, and to determine their basic characteristics, viz., phase analysis, texture quality, lattice constants, grain size, and size of the coherent scattering domain. Regimes were identified for depositing films with optimal structural characteristics for eventual use in solar-energy applications.