Novel p-type semiconductors can be found in these extraordinary comb structures. The GeSe combs are selectively formed by a vaporization-condensation-recrystallization (VCR) process using bulk GeSe powder as the precursor source. They have a flat body plate part and extended wire finger parts, both of which have identical crystal structures. The GeSe comb field-effect transistor device displays both p-type semiconducting and photo-switching behavior.