A compound semiconductor precursor ink composition includes an ink composition for forming a chalcogenide semiconductor film and a peroxide compound mixed with the ink composition. In one embodiment, a method may include determining a respective expected picking rate for each of a number of inventory items, and dependent upon the expected picking rate, selecting a corresponding one of a number of zones of an inventory storage area for each of the items. When mounted on a printed circuit board to connect two segments of a signal line, the notch filter and a ground plane of the PCB form a virtual conductive loop having an inductance and a capacitance whose product is the center frequency of the notch of the notch filter.