Provided is a semiconductor structure including a substrate, a first semiconductor layer, a second semiconductor layer, a gate electrode, a source electrode and a drain electrode. The first semiconductor layer contains a group III-V-VI semiconductor compound layer and is disposed on the substrate. The second semiconductor layer includes a group III-V semiconductor compound and is disposed on the first semiconductor layer. The gate electrode is disposed on the second semiconductor layer. The source electrode and the drain electrode are disposed on the second semiconductor layer beside the gate electrode.