Thin-film transistor, substrate and display device each having the thin-film transistor, and method of manufacturing the thin-film transistor

A method of manufacturing a thin-film transistor (TFT), the method comprising:

• forming a gate electrode;
• forming a semiconductor pattern comprising an active layer being overlapped with the gate electrode and a low band gap portion having a lower energy band gap than the active layer;
• and
• forming a source electrode and a drain electrode that are spaced apart from each other to be overlapped with the semiconductor pattern.

A thin-film transistor (TFT) substrate comprising:

• a base substrate;
• a plurality of TFTs comprising:
• a gate electrode;
• a semiconductor pattern comprising an active layer being overlapped with the gate electrode and a low band gap portion having a low energy band gap than the active layer;
• and
• a source electrode and a drain electrode that are spaced apart from each other to be overlapped with the semiconductor pattern;
• a passivation layer covering the TFT to protect the TFT;
• and
• a plurality of pixel electrodes formed on the passivation layer to be electrically connected to the TFT through a plurality of contact holes of the passivation layer.

A display device comprising:

• a thin-film transistor (TFT) substrate;
• an opposite substrate opposite to the TFT substrate;
• and
• a liquid crystal layer disposed between the TFT substrate and the opposite substrate, wherein the TFT substrate comprises:
• a base substrate;
• a plurality of TFTs comprising a gate electrode, a semiconductor pattern comprising an active layer being overlapped with the gate electrode and a low band gap portion having a low energy band gap than the active layer, and a source electrode and a drain electrode that are spaced apart from each other to be overlapped with the semiconductor pattern;
• a passivation layer covering the TFT to protect the TFT;
• and
• a plurality of pixel electrodes formed on the passivation layer to be electrically connected to the TFT through a plurality of contact holes of the passivation layer.