Transparent Electronics for See-Through AMOLED Displays

Transparent thin-film-transistors (TFTs) with a channel semiconductor based on the zinc-tin-oxide (ZTO) system are presented. Specifically, the technological and material aspects of the plasma-assisted pulsed laser deposition of these materials are discussed. The supply of additional radical oxygen species will be evidenced to significantly reduce defects in the material and as a consequence allows for well-behaved n-channel TFTs with mobilities higher than 10 cm
²
V
^-1
s
^-1
and a threshold voltage in the range of 0 V. In addition the devices are extremely stable versus bias/current stress, which is especially important for active matrix OLED applications. Based on a detailed understanding of the interaction of the TFT channels with oxygen a strategy for the thin-film encapsulation of the TFTs will be presented, which leaves their device characteristics unaffected.