Photoelectric Characteristics of a Large-Area n-MoS₂/p-Si Heterojunction Structure Formed through Sulfurization Process

• Main Authors: Yoonsok Kim, Taeyoung Kim, Eun Kyu Kim
• Format: Article
• Language: English
• Published: MDPI AG 2020-12-01
• Series: Sensors
• Subjects: MoS₂; transition metal dichalcogenide; heterojunction; photodiode
• Online Access: https://www.mdpi.com/1424-8220/20/24/7340

Two-dimensional (2D) materials, such as molybdenum disulfide (MoS₂) of the transition metal dichalcogenides family, are widely investigated because of their outstanding electrical and optical properties. However, not much of the 2D materials research completed to date has covered large-area structures comprised of high-quality heterojunction diodes. We fabricated a large-area n-MoS₂/p-Si heterojunction structure by sulfurization of MoO_x film, which is thermally evaporated on p-type silicon substrate. The n-MoS₂/p-Si structure possessed excellent diode characteristics such as ideality factor of 1.53 and rectification ratio in excess of 10⁴. Photoresponsivity and detectivity of the diode showed up to 475 mA/W and 6.5 × 10¹¹ Jones, respectively, in wavelength ranges from visible to near-infrared. The device appeared also the maximum external quantum efficiency of 72%. The rise and decay times of optical transient response were measured about 19.78 ms and 0.99 ms, respectively. These results suggest that the sulfurization process for large-area 2D heterojunction with MoS₂ can be applicable to next-generation electronic and optoelectronic devices.