Sources, devices, and techniques for deposition of organic layers, such as for use in an OLED, are provided. A vaporizer may vaporize a material between cooled side walls and toward a mask having an adjustable mask opening. The mask opening may be adjusted to control the pattern of deposition of the material on a substrate, such as to correct for material buildup that occurs during deposition. Material may be collected from the cooled side walls for reuse.