In this study, we use three common types of back contacts to CdTe-a ZnTe:Cu back-contact interface layer, a Cu/Au bilayer, and HgTe:Cu-doped graphite paste-to enable us to gain greater understanding of how back-contact processing affects the entire CdTe/CdS device. Current density-voltage (J-V) and quantum efficiency (QE) measurements are used to examine device performance and carrier collection. Variations in the CdTe net acceptor density are examined using capacitance-voltage (C-V) measurements. Temperature-dependent current density-voltage (JVT) characterization is used to investigate the back-contact barrier height. These methods enhance our understanding of contacts to CdTe and the effects of these contacts on CdTe photovoltaic devices.