Dark current suppression of amorphous selenium based photosensors by the ZnO hole blocking layer

Tung Yuan Yu, Fu-Ming Pan*, Cheng Yi Chang, Tien Hu, Jenn-Fang Chen, Jia Feng Wang, Cheng Lu Lin, Tsung Han Chen, Te Ming Chen

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    9 Scopus citations

    Abstract

    To study the influence of defects in the hole blocking layer (HBL) on the dark current of amorphous selenium (a-Se) based photosensors, we prepared ZnO thin films by reactive sputter deposition (RSD) for the use as the HBL of the photosensors. The ZnO HBL layers prepared with different oxygen flow rates were characterized by X-ray photoelectron spectroscopy, Raman scattering analysis and photoluminescence, indicating that the density of oxygen vacancies in the ZnO thin films is significantly affected by the oxygen flow rate. The deep level transient spectroscopy measurement reveals two hole trap levels present in the RSD deposited ZnO thin films; one is at 0.94 eV and the other at 0.24 eV above the valence band edge. The electrical performance of the a-Se photosensor is largely influenced by the amount of oxygen vacancies in the ZnO thin film. The a-Se photosensor with the ZnO HBL of the most oxygen vacancies has the lowest dark current and demonstrates the highest breakdown field.

    Original languageEnglish
    Pages (from-to)659-664
    Number of pages6
    JournalCurrent Applied Physics
    Volume14
    Issue number5
    DOIs
    StatePublished - 1 Jan 2014

    Keywords

    • Amorphous Se
    • DLTS
    • Hole blocking layer
    • Oxygen vacancy
    • Zinc oxide

    Fingerprint

    Dive into the research topics of 'Dark current suppression of amorphous selenium based photosensors by the ZnO hole blocking layer'. Together they form a unique fingerprint.

    Cite this