You have qarried for knowing the name of the manufacturer/s of "phosphorous coated substrate" but has not specified whether it is a black, red or yellow or conversion phosphate coating on thin, flexible or thick substrate.
Generally two types - Black phosphorous thin film on flexible film such as PE, here, a nano-crystalline thin BP film with thickness of ~40 nm for optical characterization with a band gap of about 0.28 eV, recently attacting lots of attention of physicists and materials scientists due widely electronic bandgap or a crystalline phosphate conversion coating on ferrous metals substrate to improve corrosion. If you have facility of vapor deposition, then possibley you could do it.
Try [email protected] or and Jiangsu Yuquan import & Export Co.,JIANGSU, China.
Nilabh, just for curiocity what sort of a project you are working on in IIT, Gadhinagar. I am also from Khadia, Ahmedabad. Wishing you all the best.