VACUUM EVAPORATION OF CHALCOGENIDE MATERIALS
Original Publication Date: 1990-Dec-31
Included in the Prior Art Database: 2004-Apr-05
Xerox Disclosure Journal
Imaging members for applications such as electrophotography are prepared by vacuum evaporating onto a substrate a chalcogenide material such as selenium, alloys of selenium with tellurium, arsenic, or mixtures thereof, selenium and selenium alloys doped with materials such as halogens, or the like. The substrate, typically of aluminum although other materials can be used, is incorporated into a vacuum coating apparatus. The chalcogenide material, typically in shot, pellet, or powder form, although other forms can be used, is placed in crucibles in the vacuum coating apparatus. The specific conditions for vacuum evaporation vary depending upon the proportions of components in the different selenium alloy materials utilized; typical temperature ranges for vacuum deposition are from about 300°C to about 350°C for alloys of Se-Te, from about 250°C to about 350°C for alloys of Se-As, and from about 300°C to about 350°C for alloys of Se-As-Te at a vacuum of between about 5 x 10-4 torr and about 8 x 10-5 torr for from about 10 minutes to about 25 minutes, although all of these values can be outside of the stated ranges. It is generally preferred that the substrate temperature be maintained in the range of from about 600C to about 850C during deposition. Subsequently, the coated substrates are removed from the vacuum coating apparatus and the crucibles are cleaned and washed with water to remove residual materials. Thereafter, fresh chalcogen alloy is placed in the crucibles and uncoated substrates are placed in the vacuum coating apparatus, and the process is repeated. Imaging members with two or more layers of chalcogenide materials can be made by this process by sequentially coating chalcogenides of the desired composition onto the substrate.