TY - GEN
T1 - Solution-Processed Ceria Interface Layer for Enhancing Performance of Avalanche Amorphous-Selenium Photodetectors
AU - Kannan, Haripriya
AU - Stavro, Jann
AU - Mukherjee, Atreyo
AU - Léveillé, Sébastian
AU - Kisslinger, Kim
AU - Guan, Lizhu
AU - Zhao, Wei
AU - Sahu, Ayaskanta
AU - Goldan, Amir
N1 - Funding Information:
This work was supported from the National Institutes of Health (R21 330 EB025300). Work by the author Haripriya Kannan was (partially) supported by the Schlumberger Foundation Faculty for the Future Program. The author, Lizhu Guan, gratefully acknowledges financial support from the China Scholarship Council (201808230282). We gratefully acknowledge support for instrument use, scientific and technical assistance from the Imaging Facility of CUNY Advanced Science Research Center. We gratefully acknowledge NYU Shared Instrumentation Facility and thank the support to the X-ray facility by the National Science Foundation under Award Number CRIF/CHE-0840277 and by the NSF MRSEC Program under Award Numbers DMR-0820341 and DMR-1420073.
Funding Information:
Manuscript received December 20, 2020. This work was supported from the National Institutes of Health (R21 330 EB025300). Work by the author Haripriya Kannan was (partially) supported by the Schlumberger Foundation Faculty for the Future Program. The author, Lizhu Guan, gratefully acknowledges financial support from the China Scholarship Council (201808230282). We gratefully acknowledge support for instrument use, scientific and technical assistance from the Imaging Facility of CUNY Advanced Science Research Center. We gratefully acknowledge NYU Shared Instrumentation Facility and thank the support to the X-ray facility by the National Science Foundation under Award Number CRIF/CHE-0840277 and by the NSF MRSEC Program under Award Numbers DMR-0820341 and DMR-1420073.
Publisher Copyright:
© 2020 IEEE
PY - 2020
Y1 - 2020
N2 - Photodiodes using amorphous-selenium (a-Se) have gained significant attention in medical imaging due to their avalanche phenomena. At electric fields above 70 V/μm, holes in a-Se undergo impact ionization which increases the effective sensitivity of the photodetector. However, at the high electric fields required for avalanche gain, dark current due to charge injection from metallic electrode can become a significant source of noise, limiting the dynamic range of the device. A non-insulating n-type hole blocking layer (HBL) is required to minimize the dark current noise from charge injection while conducting only electrons. Among previously reported HBLs, vacuum deposited bulk cerium dioxide (CeO2) have been successfully utilized in n-i-p avalanche a-Se sensors. However, bulk CeO2 cannot be directly deposited on a-Se and suffers from high dark current due to lower effective hole barrier for CeO2 (2.8 eV). In our work, we successfully synthesized colloidal CeO2 quantum dots (QDs) with a large bandgap (Eg = 3.77 eV), which are electronically passivated by surfactants/ligands and spin coated directly on a-Se at room temperature without inducing crystallization. Our prototype device achieved an ultra-low dark current of 30 pA/cm2 at 70 V/μm which is three orders of magnitude lower than any avalanche a-Se device previously reported and may be the lowest dark current ever recorded for an avalanche device operated at room temperature signifying the potential importance of utilization of solution-processed QDs as HBL.
AB - Photodiodes using amorphous-selenium (a-Se) have gained significant attention in medical imaging due to their avalanche phenomena. At electric fields above 70 V/μm, holes in a-Se undergo impact ionization which increases the effective sensitivity of the photodetector. However, at the high electric fields required for avalanche gain, dark current due to charge injection from metallic electrode can become a significant source of noise, limiting the dynamic range of the device. A non-insulating n-type hole blocking layer (HBL) is required to minimize the dark current noise from charge injection while conducting only electrons. Among previously reported HBLs, vacuum deposited bulk cerium dioxide (CeO2) have been successfully utilized in n-i-p avalanche a-Se sensors. However, bulk CeO2 cannot be directly deposited on a-Se and suffers from high dark current due to lower effective hole barrier for CeO2 (2.8 eV). In our work, we successfully synthesized colloidal CeO2 quantum dots (QDs) with a large bandgap (Eg = 3.77 eV), which are electronically passivated by surfactants/ligands and spin coated directly on a-Se at room temperature without inducing crystallization. Our prototype device achieved an ultra-low dark current of 30 pA/cm2 at 70 V/μm which is three orders of magnitude lower than any avalanche a-Se device previously reported and may be the lowest dark current ever recorded for an avalanche device operated at room temperature signifying the potential importance of utilization of solution-processed QDs as HBL.
KW - Amorphous selenium
KW - Avalanche photodiode
KW - Cerium dioxide
KW - Dark current
KW - Hole blocking layer
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UR - http://www.scopus.com/inward/citedby.url?scp=85124696283&partnerID=8YFLogxK
U2 - 10.1109/NSS/MIC42677.2020.9507944
DO - 10.1109/NSS/MIC42677.2020.9507944
M3 - Conference contribution
AN - SCOPUS:85124696283
T3 - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2020
BT - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2020
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2020 IEEE Nuclear Science Symposium and Medical Imaging Conference, NSS/MIC 2020
Y2 - 31 October 2020 through 7 November 2020
ER -