Rams boss Nigel Clough wants to strengthen his attacking options and is hoping he can lure teenage Frenchman Sunu or recall 21-year old Vaughan to Pride Park.
Vaughan was on loan at Derby earlier this season and Sunu has been in talks with the club leaving Clough hopeful of a move for one of the duo.
"Nothing has changed with the two players. We are still chasing them and would like to add one of the two to our squad," said Clough.
"We will pursue it again this week. With Steve Davies out, we are a bit light in the striking department."