Large Area Digital X‐ray Imaging

This chapter reviews amorphous silicon devices for large area flat panel imaging technology. We present Schottky and p-i-n diode image sensors and elaborate on their operating principles, electrical and optoelectronic characteristics including stability, along with the challenges associated with reduction of the dark current. Issues pertinent to sensor-thin film transistor integration for different active matrix pixel architectures for high fill factor imaging arrays are presented along with optimization of materials and processing conditions for reduced threshold voltage shift, reduced parasitics and leakage current, and enhanced mechanical integrity. Extension of the current fabrication processes to low (∼120°C) temperature, enabling fabrication of flexible imaging array (on plastic substrates), is also discussed.