A p-type ZnO semiconductor film comprised mainly of Zn and O elements is disclosed. The film is characterized as containing an alkali metal and nitrogen. Preferably, the alkali metal is contained such that its concentration is distributed to increase toward an end or toward both ends in the thickness direction of the film. More preferably, the alkali metal is contained in the concentration range of 1.times.10.sup.18-5.times.10.sup.21 cm.sup.-3 and the nitrogen in the concentration range of 2.times.10.sup.17-5.times.10.sup.20 cm.sup.-3.