A transistor may include a hole blocking layer between a channel layer including oxynitride and an electrode electrically connected to the channel layer. The hole blocking layer may be disposed in a region between the channel layer and at least one of a source electrode and a drain electrode. The channel layer may include, for example, zinc oxynitride (ZnON). A valence band maximum energy level of the hole blocking layer may be lower than a valence band maximum energy level of the channel layer.