High photoresponsivity from multilayer MoS2/Si heterojunction diodes formed by vertically stacking

• Published in: Journal of applied physics 2017-09, Vol.122 (12)
• Main Authors: Song, Da Ye, Chu, Dongil, Lee, Seung Kyo, Pak, Sang Woo, Kim, Eun Kyu
• Format: Article
• Language: English
• Subjects: Applied physics; Dependence; Heterojunctions; Incident light; Light emitting diodes; Luminous intensity; Molybdenum disulfide; Multilayers; Near infrared radiation; Organic light emitting diodes; Silicon substrates
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.4994740

We investigated a vertically stacked p+-n heterojunction diode consisting of a two-dimensional (2D) molybdenum disulfide (MoS2) crystal and a heavily doped p+-type Si substrate. The MoS2 flakes are transferred onto p+-Si substrates by using a scotch tape-based exfoliation method. The performances of n-MoS2/p+-Si diodes are investigated by I-V measurement under light illumination using light emitting diodes with various wavelengths. It appears that multilayer MoS2 has sufficient thickness to absorb incident light from the visible to near-infrared range with a high sensitivity. With the advantages of a simple device structure as well as improved contact quality between the MoS2 and silicon interface, an ideality factor of 1.09 can be achieved. The diodes reveal an ultra-high photoresponsivity of about 980 A/W at a wavelength of 525 nm with a strong dependence on the light wavelength and intensity, while they show a high specific detectivity on the order of 109 cm·Hz1/2/W from the visible to near infrared spectral ranges.