Silicon based near infrared photodetector using self-assembled organic crystalline nano-pillars

Yoshiharu Ajiki, Tetsuo Kan, Masayuki Yahiro, Akiko Hamada, Junji Adachi, Chihaya Adachi, Kiyoshi Matsumoto, Isao Shimoyama

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

We propose a silicon (Si) based near-infrared photodetector using self-assembled organic crystalline nano-pillars, which were formed on an n-type Si substrate and were covered with an Au thin-film. These structures act as antennas for near-infrared light, resulting in an enhancement of the light absorption on the Au film. Because the Schottky junction is formed between the Au/n-type Si, the electron excited by the absorbed light can be detected as photocurrent. The optical measurement revealed that the nano-pillar structures enhanced the responsivity for the near-infrared light by 89 (14.5 mA/W) and 16 (0.433 mA/W) times compared with those of the photodetector without nano-pillars at the wavelengths of 1.2 and 1.3 μm, respectively. Moreover, no polarization dependency of the responsivity was observed, and the acceptable incident angle ranged from 0°to 30°. These broad responses were likely to be due to the organic nano-pillar structures' having variation in their orientation, which is advantageous for near-infrared detector uses.

Original languageEnglish
Article number151102
JournalApplied Physics Letters
Volume108
Issue number15
DOIs
Publication statusPublished - Apr 11 2016

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy (miscellaneous)

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