Effect of X-Ray Irradiation on Colloidal Quantum Dot SWIR CMOS Image Sensor

Abstract

In this article, the X-ray radiation effects on colloidal quantum dot photodiode (QDPD)-based short-wave infrared (SWIR) complementary metal-oxide semiconductor image sensors (QD-CISs) are studied. Individual QDPD, silicon readout IC (Si-ROIC), and QD-CIS are evaluated together for a comprehensive analysis. The dark current, activation energy, and external quantum efficiency (EQE) of samples are investigated before and after irradiating with 58.2 keV of X-ray radiation, which has a different total ionizing dose (TID) range from 22 to 220 krad. X-ray irradiation on Si-ROIC induces mid-band gap trap states and increases the dark current according to the increasing TID. However, for the QDPD, despite an increase in the TID, the dark current reduces and the EQE slightly enhances at the SWIR wavelength. The QD-CIS shows a decrease in the dark current like the QDPD results, as the TID increases. The activation energy of QD-CIS rarely changes regardless of TID amounts. The X-ray radiation effect on QDPD results in enhanced performance, and this effect continues in the integrated QD-CIS, whereas the effect of Si-ROIC degradation is minor in the current experimental range. Thus, these findings provide significant insights into the utilization of QD-CIS in various X-ray applications.