Sensor readout circuit using AOSTFTs for IGZO (In-Ga-ZnO) sensors

In this work, we present two simple readout circuits, using amorphous oxide semiconductor thin film transistor (AOSTFT), to be used with a photoconductivity amorphous semiconductor sensor that detects volatile organic solvent. One circuit uses IGZO TFTs with 5 V operating voltage, and the other uses HIZO TFTs with 3 V operating voltage. The specifics of the circuits are analyzed, and their validation is done by Smartspice simulation. Both readout circuits, with IGZO and HIZO TFTs, have the advantage of the fabrication process compatibility of the sensor and the readout circuit. Another advantage is the possibility of portable applications, due to the reduced operating voltage of 5 V, and even 3 V in the case of HIZO circuit.