Indium gallium zinc oxide
Indium gallium zinc oxide (IGZO) is a semiconducting material, consisting of indium (In), gallium (Ga), zinc (Zn) and oxygen (O), and often abbreviated as "IGZO". IGZO thin-film transistor (TFT) is used in the TFT backplane of flat-panel displays (FPDs). IGZO-TFT was developed by Professor Hideo Hosono's group at Tokyo Institute of Technology and Japan Science and Technology Agency (JST) in 2003 (crystalline IGZO-TFT) and in 2004 (amorphous IGZO-TFT). IGZO-TFT has 20-50 times higher mobilities than that of amorphous silicon, which has been used for current liquid-crystal displays (LCDs) and electronic papers; therefore, IGZO-TFT can improve operation speed, resolution and size of flat-panel displays, and is also considered as one of the most promising thin-film transistors to drive organic light-emitting diode (OLED) displays.
Sharp started the world's first production of LCD panels Incorporating IGZO-TFT in 2012. Sharp employs IGZO-TFT for smartphones, tablets, 32" LCD, etc, in which the aperture ratio of the LCD is improved by up to 20%, and power consumption is improved by LCD idling stop technology owing to the high mobility and low off current of IGZO-TFT. Sharp started to release high pixel-density panels for notebook applications. IGZO-TFT is also employed in 14" 3,200x1,800 LCD of an ultrabook PC supplied from Fujitsu and 55" OLED TV supplied from LG Electronics.
Its advantage over zinc oxide is that it can be deposited as a uniform amorphous phase while retaining the high carrier mobility common to oxide semiconductors. The transistors are slightly photo-sensitive, but the effect becomes significant only in the deep violet to ultra-violet (photon energy above 3 eV), offering the possibility of a fully transparent transistor.