Characterization of optically sensitive amorphous selenium photodetector at high electric fields

Saeedeh Ghaffari; Shiva Abbaszadeh; Sina Ghanbarzadeh; Karim S. Karim

doi:10.1109/TED.2015.2436818

Characterization of optically sensitive amorphous selenium photodetector at high electric fields

Saeedeh Ghaffari, Shiva Abbaszadeh, Sina Ghanbarzadeh, Karim S. Karim

Research output: Contribution to journal › Article › peer-review

Abstract

We investigated the electrical conduction in indium tin oxide/polyimide (PI)/amorphous selenium/Au device structures, operated at high fields (up to 40 V/μm). Devices having different PI thicknesses (0.4-2.5 μm) with the same thickness of a-Se (16 μm) were fabricated, and the dark and photocurrent transient behavior of each device under different biasing voltages was tested. The results indicate that an optimal thickness of PI (∼ 1 μm) was necessary to limit the dark current to below 10 pA/mm² while achieving an on/off ratio of 10⁴, a result not achievable in devices without the PI layer. Furthermore, time-of-flight (TOF) measurements at low electric fields (∼ 10 V/μm) were carried out to measure the exact voltage drop within the PI and a-Se films for the same structure. Based on these TOF measurements, the electric field within the PI layer was determined to reach 138 V/μm to provide efficient electrical conduction for photogenerated electrons.

Original language	English (US)
Article number	7118668
Pages (from-to)	2364-2366
Number of pages	3
Journal	IEEE Transactions on Electron Devices
Volume	62
Issue number	7
DOIs	https://doi.org/10.1109/TED.2015.2436818
State	Published - Jul 1 2015
Externally published	Yes

Keywords

Amorphous selenium (a-Se)
optical detectors
polyimide (PI)
time of flight (TOF)

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Electrical and Electronic Engineering

Online availability

10.1109/TED.2015.2436818

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title = "Characterization of optically sensitive amorphous selenium photodetector at high electric fields",

abstract = "We investigated the electrical conduction in indium tin oxide/polyimide (PI)/amorphous selenium/Au device structures, operated at high fields (up to 40 V/μm). Devices having different PI thicknesses (0.4-2.5 μm) with the same thickness of a-Se (16 μm) were fabricated, and the dark and photocurrent transient behavior of each device under different biasing voltages was tested. The results indicate that an optimal thickness of PI (∼ 1 μm) was necessary to limit the dark current to below 10 pA/mm2 while achieving an on/off ratio of 104, a result not achievable in devices without the PI layer. Furthermore, time-of-flight (TOF) measurements at low electric fields (∼ 10 V/μm) were carried out to measure the exact voltage drop within the PI and a-Se films for the same structure. Based on these TOF measurements, the electric field within the PI layer was determined to reach 138 V/μm to provide efficient electrical conduction for photogenerated electrons.",

keywords = "Amorphous selenium (a-Se), optical detectors, polyimide (PI), time of flight (TOF)",

author = "Saeedeh Ghaffari and Shiva Abbaszadeh and Sina Ghanbarzadeh and Karim, {Karim S.}",

note = "Publisher Copyright: {\textcopyright} 2015 IEEE.",

year = "2015",

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AU - Ghaffari, Saeedeh

AU - Abbaszadeh, Shiva

AU - Ghanbarzadeh, Sina

AU - Karim, Karim S.

PY - 2015/7/1

Y1 - 2015/7/1

N2 - We investigated the electrical conduction in indium tin oxide/polyimide (PI)/amorphous selenium/Au device structures, operated at high fields (up to 40 V/μm). Devices having different PI thicknesses (0.4-2.5 μm) with the same thickness of a-Se (16 μm) were fabricated, and the dark and photocurrent transient behavior of each device under different biasing voltages was tested. The results indicate that an optimal thickness of PI (∼ 1 μm) was necessary to limit the dark current to below 10 pA/mm2 while achieving an on/off ratio of 104, a result not achievable in devices without the PI layer. Furthermore, time-of-flight (TOF) measurements at low electric fields (∼ 10 V/μm) were carried out to measure the exact voltage drop within the PI and a-Se films for the same structure. Based on these TOF measurements, the electric field within the PI layer was determined to reach 138 V/μm to provide efficient electrical conduction for photogenerated electrons.

AB - We investigated the electrical conduction in indium tin oxide/polyimide (PI)/amorphous selenium/Au device structures, operated at high fields (up to 40 V/μm). Devices having different PI thicknesses (0.4-2.5 μm) with the same thickness of a-Se (16 μm) were fabricated, and the dark and photocurrent transient behavior of each device under different biasing voltages was tested. The results indicate that an optimal thickness of PI (∼ 1 μm) was necessary to limit the dark current to below 10 pA/mm2 while achieving an on/off ratio of 104, a result not achievable in devices without the PI layer. Furthermore, time-of-flight (TOF) measurements at low electric fields (∼ 10 V/μm) were carried out to measure the exact voltage drop within the PI and a-Se films for the same structure. Based on these TOF measurements, the electric field within the PI layer was determined to reach 138 V/μm to provide efficient electrical conduction for photogenerated electrons.

KW - Amorphous selenium (a-Se)

KW - optical detectors

KW - polyimide (PI)

KW - time of flight (TOF)

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Characterization of optically sensitive amorphous selenium photodetector at high electric fields

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