Extended Gate Field-Effect Transistor Based on Quantum Dots Porous Silicon with Silver Nanowires for X-ray Dosimeter Applications

Abstract

The development of a sensitive and reliable design of the extended gate field effect transistor (EGFET) for X-ray dosimeter is in demand for the measurement of radiation dose in several fields including diagnostic and interventional radiology. Here, porous silicon quantum dot (PSi-QD) was prepared from n-type silicon (100) using the photo–electrochemical etching technique and tested as an EGFET for X-ray detection. Well-defined crystalline silver nanowires (AgNWs) have been incorporated on the surface of bare PSi-QD through dropping a homogeneous AgNWs solution. The crystal structure and surface morphology of the prepared PSi-QD and AgNWs/PSi-QD were analyzed using X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM), respectively. The voltage sensitivity and linearity of both structures were then examined using low absorbed doses of 10, 39, and 59 mGy. The PSi-QD and AgNWs/PSi-QD EGFETs displayed voltage sensitivity and linearity values of 2.3 mV/mGy and 88.63%, and 3.0 mV/mGy and 94.44%, respectively. Furthermore, the measured sensitivity of the PSi-QD EGFET decreased from 2.9 mV/mGy to 2.2 mV/mGy, while that of AgNWs/PSi-QD EGFET reduced from 7.6 mV/mGy to 3.3 mV/mGy with increase in the absorbed dose from 10mGy to 59 mGy. Based on its high voltage sensitivity and good linearity as well as its good repeatability and measurable radiation sensitivity, the AgNWs/PSi-QD EGFET can be considered an effective and functional radiation dosimeter for X-ray detection.