The most common semiconducting layer is made of amorphous silicon (a-Si). a-Si thin film transistor - liquid crystal display (TFT-LCD) has been the dominant technology for the manufacturing of active matrix TFT-LCD for over 20 years.
a-Si is a low cost material in abundant supply. However, the electron mobility of a-Si is very low (around 1cm2/Vs) and can’t physically support high refresh rates such as the 240Hz needed for HDTV. Due to their high electron mobility, new materials such as metal oxide (MO)and low temperature polysilicon (LTPS) are now replacing a-Si to manufacture the industry’s two main types of screens: LCD and organic light-emitting diode (OLED) displays.