Students own the copyright of their works under most circumstances. Works created by students while employed by the university are institutional works, but otherwise, students own the rights.
From Minnesota State Board Policy 3.26 Intellectual Property, Part 4, Subpart A, no. 4:
Intellectual property rights in a student work belong to the student who created the work. A work created by a student to meet course requirements using college or university resources for which the student has paid tuition and fees to access courses/programs or using resources available to the public, is the property of the student. A work created by a student employee during the course and scope of employment is an institutional work and the intellectual property rights belong to the college or university unless an agreement, sponsorship agreement, internship agreement, or other condition described in Subpart B or C provides otherwise.
NOTE: Joint authorship of works does not split the ownership of copyright. Each person who contributed to the whole has equal ownership.