Spatially resolved current- and photodetection based on amorphous indium gallium zinc oxide

Abstract

In the scope of this thesis amorphous indium gallium zinc oxide based thin-film devices and circuits are utilized to create current- and photodetection arrays. These arrays enable the spatial resolution of the charge carrier creation, the electric field distribution and the fluorescence light inside a nitric oxide sensing cell. The experimental setup including the gas cell is part of the quantum nitric oxide sensing experiment, whose goal is to realize a trace gas sensor for the detection of nitric oxide. The sensor principle is based on the thermal ionization of resonant excited electronic states. Thin-film technology can provide an integrated readout of the ionization current. Therefore the development, simulation and characterization of the required current-to-voltage conversion circuits (resistive transimpedance amplifiers) takes up a considerable part of this thesis. Especially the creation of an on-glass unity gain stable operational amplifier design is treated extensively. This includes a theoretical overview on different current-to-voltage converters, operational amplifiers, thin-film devices and technology. A variation of thin-film based photosensing devices is manufactured and characterized. The characterization includes the investigation of the detection efficiency, the sensitivity and the bandwidth. Furthermore the influence of sensor dimensions and operating parameters on the sensor characteristics is determined. Additional the compatibility of photosensors and transistors or readout circuits are elaborated. The functionality of the photosensor arrays is validated by measuring the beam size of an ultraviolet laser at 227 nm. In general the created thin-film devices and circuit have applications in the display field, especially in the subfield of sensor integration into displays. Transimpedance amplifiers can be essential parts in the readout circuits of these sensors. The utilized operational amplifier also has an application in column and row driver circuits of displays.