Optical design of infrared thin-film photodetectors

Leuven - Master projects/internships
More than two weeks ago

Boosting the performance of colloidal quantum dot based infrared sensors using the combination of experiments (metrology) and simulations (python).

Most modern infrared photodiode arrays combine a silicon based backplane with an infrared absorbing material. These thick substrates are flip-bonded to the backplanes, which limits the pixel resolution. Processing directly on top of a silicone backplane will increase the pixel density and decreases the production cost. At the same time, this solution will create options to fabricate flexible photodetectors, processing the infrared materials on sheets in combination with flexible electronics. In the recent years, colloidal quantum dots received an increasing amount of attention due to their opto-electronic properties, with applications in light-emitting diodes and photovoltaics. Once the size of a nanoparticle reaches the exciton Bohr radius, quantum confinement effects will affect both the light absorption and emission spectrum of the material. By starting from a bulk material with infrared absorbing properties, one can obtain visible or infrared absorbing quantum dots. The quantum dots are typically surrounded by organic ligands that stabilize the material. The material can be made soluble by selecting the correct ligand. Moreover, these ligands can limit the large surface recombination inherent to the small quantum dots. The focus of this internship will be on the optical aspects of such an IR absorbing stack. The involved layers will be measured using ellipsometry to obtain the complex index of refraction, depending on the ligand termination. Using a custom build transfer matrix based optical simulator, you will determine the best stack layout for the highest performance. These stacks will be matched with experimental values. If applicable, the student will receive training on the relevant processing and characterization tools. After a short introduction to the facilities, an independent investigation is expected with the focus on short-term research goals.

Type of project: Internship, Thesis, Combination of internship and thesis

Duration: >6 months

Required degree: Master of Engineering Technology, Master of Science, Master of Engineering Science

Required background: Chemistry/Chemical Engineering, Electrotechnics/Electrical Engineering, Materials Engineering, Nanoscience & Nanotechnology, Physics

Supervising scientist(s): For further information or for application, please contact: David Cheyns (David.Cheyns@imec.be) and Epimitheas Georgitzikis (Epimitheas.Georgitzikis@imec.be)

Imec allowance will be provided

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