High responsivity of VIS-NIR photodetector based on Ag₂S/P3HT heterojunction

Abstract

Ag2S quantum dot (QD) photodetectors (PDs) have attracted a lot of attention in the field of imaging system and optical communication. However, the current Ag2S PDs mainly works in the near-infrared band, and its detection ability in the visible band remains to be strengthened. In this paper, we used poly(3-hexylthiophene) (P3HT) with high carrier mobility and Ag2S QDs to construct heterojunction PD. Stronger absorption in blends with polymer P3HT compared to single Ag2S QDs. The optical absorption spectra show that the Ag2S/P3HT has strong light absorption peak at 394 nm and 598 nm. The results show that P3HT significantly enhances the absorption of Ag2S QDs from the visible to near-infrared band. The output characteristics, transfer characteristics and fast switching capability of the device at 405 nm, 532 nm and 808 nm were tested. The device has the responsivity of 6.05 A/W, 83.72 A/W and 37.31 A/W under 405 nm, 532 nm, and 808 nm laser irradiation. This work plays an important role in improving the detection performance of Ag2S QDs and broadening its applications in photoelectric devices for weak light and wide spectrum detection.

Near Ultraviolet Photoresponse of a Silicon Carbide and Tantalum Boride Heterostructure

“…6 (a), the responsivity for powers between 730 μW and 7 mW (power densities of 78.77 W/m 2 and 755 W/m 2 , respectively) increases from 0.06 to 0.15 A/W when the applied voltage is changed from -0.4 to -1 V (calculated by dividing the current by the incident power). For low powers (Popt<730 μW), the responsivity is higher than in the linear region (for powers between 730 μW and 7 mW): similar response was observed by Wang et al [28]. The explanation of the high responsivity at low powers can be attributed to the initial filling of defect and trap states that become filled at higher powers.…”

“…where q is the elementary charge, η is the quantum efficiency, λ= 405 nm is the operating wavelength, hplanck is the Planck's constant and c light is the speed of light in vacuum, then the quantum efficiency is 18% at -0.4 V and 46% at -1 V. The detectivity (D * ) is an important parameter of the photodetector, which is calculated as [28],…”

Photodetectors integrating waveguides and semiconductor materials

“…129,130 VIS photodetectors also play a significant role in these applications. 131 The Si 3 N 4 material has good transmittance for the VIS band, and is one of the better candidates as a VIS light waveguide. 124 However, most of the research on photodetectors based on photonic platforms has focused on the IR telecommunication band, and there is still relatively little research on integrated waveguides and semiconductor materials for VIS photodetectors.…”