An employee who creates a work within the scope of his or her employment produces a "work for hire". The copyright of a work for hire is owned by the employer. However, this is not automatic. A "work for hire" must be written into the contract. This is an important issue for faculty to consider. The contract with your institution may supersede your copyrights as regards your research and writing. If this has not been put into writing, perhaps it is something that ought to be addressed to protect both parties.
For more information about "work for hire" see the Library of Congress Copyright Circular 9 "Works Made for Hire under the 1976 Copyright Act".