Si:HgTe Colloidal Quantum Dots Heterojunction-Based Infrared Photodiode

Integrated circuits and optoelectronics are currently dominated by silicon technology. However, silicon’s response wavelength is typically less than 1,100 nm, limiting the application of silicon in machine vision, autonomous vehicles, and night vision. For infrared photodetectors, HgTe colloidal quantum dots (CQDs) are promising materials. Because of the adjustable bandgap, it responds over a wide spectral range. However, the construction of a high-quality junction between Si and HgTe CQDs continues to be difficult, thus restricting the scope of its application. In this article, we describe the synthesis, characterization, and correlation of HgTe CQDs with reaction temperature and nanocrystal size. We then fabricated HgTe-CQDs/silicon infrared photodiodes and discussed how the silicon resistivity affected their performance. We found that the devices prepared from 9.1 nm HgTe quantum dots synthesized at 80°C and a silicon substrate with a resistivity of 20–50 Ω·cm has optimal performance parameters. This results in a responsivity of 0.2 mA/W for 1,550 nm incident light at room temperature. These results provide a direction for future silicon-compatible HgTe quantum dot infrared optoelectronics.