title: The n-type Ge photodetectors with gold nanoparticles deposited to enhance the responsivity.
abstract: Gold nanoparticles (AuNPs) have been deposited on n-type Ge photodetectors to improve the responsivity. Two different coverage ratios, including 10.5 and 30.3% of AuNPs have been prepared, and the fabricated photodetectors are compared with the control sample. The 1,310-nm responsivities at -2 V of the control, 10.5% AuNPs, and 30.3% AuNPs samples are 465, 556, and 623 mA/W, respectively. The AuNPs could increase the responsivities due to the plasmon resonance. The reflectance spectra of these samples have been measured to verify that plasmon resonance contributes to the forward scattering of incident light. The reflectance decreases with AuNP deposition, and a denser coverage results in a smaller reflectance. The smaller reflectance indicates more light could penetrate into the Ge active layer, and it results in a larger responsivity.
authors.affiliation: Department of Opto-electronic Engineering, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan.
authors.forename: Hao-Tse
authors.initials: HT
authors.lastname: Hsiao
authors.affiliation: Department of Physics, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan.
authors.forename: I-Chih
authors.initials: IC
authors.lastname: Ni
authors.affiliation: Department of Physics, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan.
authors.forename: Shien-Der
authors.initials: SD
authors.lastname: Tzeng
authors.affiliation: Department of Opto-electronic Engineering, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan.
authors.forename: Wei-Fan
authors.initials: WF
authors.lastname: Lin
authors.affiliation: Department of Opto-electronic Engineering, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan.
authors.forename: Chu-Hsuan
authors.initials: CH
authors.lastname: Lin
keywords: AuNP; Ge photodetector; Responsivity