A study on SWIR CQD photodiode architecture for image sensors

In recent years, there has been a significant increase in the integration of infrared image sensors in many everyday-use devices such as smartphones and laptops, driven by the need for biometric sensors such as face recognition and fingerprint scanners. 

At the same time, a variety of new applications such as autonomous vehicles, augmented reality (AR), virtual reality (VR) can take advantage of developments in infrared imaging technology. Specifically, a growing demand exists for sensing technologies in the short-wave-infrared (SWIR), which relates to wavelengths in the range of 1µm-2µm. Nowadays, the available technologies for IR sensors are rather limited. Silicon can only be detected in the near-infrared range (NIR) with a strong cut-off after 900 nm and the III-V semiconductors that are used for SWIR spectrum have constraints in terms of throughput, resolution, and high fabrication cost. 

Colloidal quantum dots (QDs) based thin-film photodetectors (TFPDs) offer an alternative approach in detecting infrared light. Taking advantage of quantum confinement, QDs, depending on their size can be tuned to detect different spectra from visible up to the NIR and SWIR. Furthermore, they can be deposited from solution over large area with low-cost techniques such as spin coating.

The main challenge in this technology is the stack development of QD TFPDs to extend utilization for the various applications. The student will focus on the devi for CQD layers under various stress environments. The main task will be performed with proper device designs (band alignment and optical), which are crucial for high detectivity. Using device physics, the student will dive deep into the optical/electrical factors of CQD-TFPDs for high detectivity. The student will also be involved in the full fabrication from the ligand exchange and film formation to the photodiode performance. He/she will receive training on the relevant processing and characterization tools. After a short introduction to the facilities, an independent investigation focusing on short-term research goals is expected.

Type of Project: Combination of internship and thesis

Master's degree: Master of Engineering Science

Master program: Materials Engineering; Nanoscience & Nanotechnology; Electrotechnics/Electrical Engineering

Duration: 1 year

Supervisor:  Jan Genoe (EE, Nano)

For more information or application, please contact the supervising scientists Sangyeon Lee (sangyeon.lee@imec.be) and Wenya Song (wenya.song@imec.be).

Only for self-supporting students.