Hi @alisongn and welcome to the forums. Unfortunately we don't have a method of contacting a specific drive here, as this website has no affiliation with Uber.
I'd recommend reaching out to Uber support. Please be prepared to offer your driver a cash tip to return your phone, since he or she may be going out of his/her way.
Another option, once you've contacted the driver thru support, is to order an Uber trip origination from his location and ending at your location. Whichever driver gets the trip will transport your phone instead of a person.