Recent studies of thin-film CdS/CdTe photovoltaic (PV) devices have suggested that significantly higher device performance will not be achieved unless recombination in the CdTe is reduced. Specifically, unless high recombination in the CdTe quasi-neutral region is reduced, benefits of increasing CdTe net-acceptor doping cannot be realized—because resulting higher open-circuit voltage will be accompanied by lower fill factor. Although some control of CdTe recombination has been achieved historically through the careful incorporation of oxygen, chlorine, and copper, many technologists believe a more promising avenue to higher device performance is by understanding and controlling the defects in the as-deposited CdTe. This is supported by theoretical studies that suggest much of the improvement associated with oxygen, chlorine, and copper is due to the interaction of these species with intrinsic defects related cadmium and tellurium (i.e., vacancies, interstitial, and anti-site defects). Although CdTe is a relatively simple semiconducting material that exists only near its 50%/50% composition, even at thermodynamic equilibrium, the material can sustain a small stoichiometric deficiency (~0.01%). Even this small extent of stoichiometry variation can produce intrinsic defects at a sufficient concentration to significantly alter device performance. Further, the typical techniques used in PV film deposition are not equilibrium processes, and so the extent of non-stoichiometry could be greater. Several research projects at NREL are currently focused on altering CdTe deposition and post-deposition processes to allow for an enhanced control of the as-deposited intrinsic defects. Related defect changes are being assessed using a combination of device analysis, time-resolved photoluminescence, low-temperature photoluminescence, and microscopic techniques. The presentation will discuss initial results where process changes expected to alter the as-deposited defects also affect junction evolution and device functionality. This abstract is subject to government rights.