Improved electrical properties of Ga2O3

Sn/CIGS hetero-junction photoconductor

Kenji Kikuchi, Shigeyuki Imura, Kazunori Miyakawa, Hiroshi Ohtake, Misao Kubota, Eiji Ohta

Research output: Contribution to journalArticle

Abstract

We examined the potential application of CuIn1-xGaxSe1-ySy (CIGS) film for visible light image sensors. CIGS chalcopyrite semiconductors, which are representative of high efficiency thin film solar cells, have both a high absorption coefficient and high quantum efficiency. However, their dark current is too high for image sensors. In this study, we applied gallium oxide (Ga2O3) as a hole-blocking layer for CIGS thin film to reduce the dark current. The dark current of this hetero-junction was 10-9 A/cm2 at less than 7 V. Moreover, an avalanche multiplication phenomenon was observed at an applied voltage of over 8 V. However, this structure had sensitivity only in the ultraviolet light region due to the much lower carrier density of the Ga2O3 layer. We therefore used a tin-doped Ga2O3 (Ga2O3:Sn) layer deposited by pulsed laser deposition (PLD) for the n-type layer to increase the carrier density. The sensitivity of the visible region was observed in the Ga2O3:Sn/CIGS hetero-junction. We also investigated the influence of the laser frequency of the PLD on the transmittance of Ga2O3:Sn and the quantum efficiency of this hetero-junction. Ga2O3:Sn film deposited at a 0.1-Hz laser repetition rate had higher transmittance than at a 10-Hz repetition rate. The Ga2O3:Sn/CIGS hetero-junction also had a higher quantum efficiency with the lower rate (50%) than with the higher rate (30%).

Original languageEnglish
Article number104
JournalPrehospital and Disaster Medicine
Volume1635
Issue number3
DOIs
Publication statusPublished - 2014 Nov 7

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Lasers
Avalanches
Semiconductors
Tin
Ultraviolet Rays
Light

Keywords

  • photoconductivity
  • sensor
  • thin film

ASJC Scopus subject areas

  • Emergency
  • Emergency Medicine

Cite this

Kikuchi, K., Imura, S., Miyakawa, K., Ohtake, H., Kubota, M., & Ohta, E. (2014). Improved electrical properties of Ga2O3: Sn/CIGS hetero-junction photoconductor. Prehospital and Disaster Medicine, 1635(3), [104]. https://doi.org/10.1557/opl.2014.104

Improved electrical properties of Ga2O3 : Sn/CIGS hetero-junction photoconductor. / Kikuchi, Kenji; Imura, Shigeyuki; Miyakawa, Kazunori; Ohtake, Hiroshi; Kubota, Misao; Ohta, Eiji.

In: Prehospital and Disaster Medicine, Vol. 1635, No. 3, 104, 07.11.2014.

Research output: Contribution to journalArticle

Kikuchi, K, Imura, S, Miyakawa, K, Ohtake, H, Kubota, M & Ohta, E 2014, 'Improved electrical properties of Ga2O3: Sn/CIGS hetero-junction photoconductor', Prehospital and Disaster Medicine, vol. 1635, no. 3, 104. https://doi.org/10.1557/opl.2014.104
Kikuchi, Kenji ; Imura, Shigeyuki ; Miyakawa, Kazunori ; Ohtake, Hiroshi ; Kubota, Misao ; Ohta, Eiji. / Improved electrical properties of Ga2O3 : Sn/CIGS hetero-junction photoconductor. In: Prehospital and Disaster Medicine. 2014 ; Vol. 1635, No. 3.
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