The Optical Materials Engineering Laboratory (Prof. David J. Norris) in the Department of Mechanical and Process Engineering (D-MAVT) at ETH Zurich investigates the synthesis, growth, structure, and optical properties of nanomaterials. Our interdisciplinary and international team combines materials chemistry, optical spectroscopy, electron microscopy, theoretical modeling, and numerical simulation to understand and control materials at the nanoscale.

Nanometer-scale semiconductor crystallites exhibit optical properties (e.g., absorption and emission spectra) that are strongly dependent on their size. Because this property is useful for creating tunable optical materials for optoelectronic applications ranging from displays and infrared cameras to nanophotonics and quantum technologies, chemical syntheses have been developed that produce nanocrystals from various semiconductors. The most advanced protocols are those that lead to quasi-spherical particles (known as colloidal quantum dots). However, even state-of-the-art nanocrystal samples contain distributions in particle size and morphology that limit their optical performance.

Two classes of semiconductor nanocrystals have been discovered as exceptions to this rule. They display an unusual form of "discrete" growth, jumping between a series of specific sizes. In particular, "magic-sized" nanocrystals grow through a sequence of well-defined sizes. This observation suggests that nanocrystals with exceptionally precise dimensions may be possible.

The central aim of this project is to determine how closely individual magic-sized nanocrystals approach atomic-scale perfection and how their size, shape, composition, surface chemistry, and structure influence their optical properties. Advanced single-particle microscopy and spectroscopy will be used to uncover variations that are hidden in conventional measurements. The resulting understanding will guide the synthesis and optimization of semiconductor nanocrystals for applications requiring highly uniform optical properties.

The doctoral student will characterize semiconductor nanocrystals using complementary optical and structural experimental techniques. The initial focus will be on CdSe magic-sized nanocrystals, with the work subsequently expanding to nanocrystals of different sizes, compositions, surface treatments, and heterostructures, including core/shell and InP nanocrystals.

The project will investigate how variations in nanocrystal size, shape, composition, surface chemistry, and structure influence optical properties. Ensemble and single-particle spectroscopy will be used to quantify optical heterogeneity and determine how closely magic-sized nanocrystals approach atomic-scale perfection. Measurements will examine properties such as emission linewidths, excited-state dynamics, spectral fluctuations, and the suitability of selected nanocrystals as single-photon emitters.

These optical studies will be complemented by advanced structural characterization. In particular, the student will use cryogenic electron microscopy and single-particle analysis to determine the three-dimensional structures of semiconductor nanocrystals with near-atomic or atomic-scale resolution. The experiments will examine nanocrystal shape, including the possible truncation of tetrahedral magic-sized nanocrystals, and how it varies with particle size, material composition, surface treatment, and isolation procedure.

The doctoral student will work closely with researchers responsible for nanocrystal synthesis and theoretical modeling. This interaction is central to the project: advanced samples will be supplied for optical and structural measurements, while the characterization results will guide improvements in nanocrystal synthesis, surface treatment, and structural control. The experiments will use the laboratory’s optical microscopy and spectroscopy infrastructure as well as the state-of-the-art electron microscopy facilities available at ETH Zurich. In addition to research, the doctoral candidate will contribute to general laboratory activities and will have opportunities to participate in teaching and the supervision of bachelor’s and master’s students.

We are seeking a curious, motivated, and self-driven candidate with a strong interest in the experimental characterization of nanoscale materials. Applicants must hold, or be close to completing, an MSc degree in chemistry, chemical engineering, materials science, mechanical engineering, nanoscience, physics, or a closely related discipline. Experience in one or more of the following areas would be advantageous:

• Optical spectroscopy or microscopy
• Time-resolved or single-particle measurements
• Electron microscopy
• Image processing, three-dimensional reconstruction, or single-particle analysis
• Semiconductor nanocrystals, quantum dots, or other nanoscale materials
• Machine learning
• Scientific programming and quantitative data analysis

Prior experience with every technique used in the project is not required. The successful candidate should, however, have a strong experimental and quantitative foundation and an enthusiasm for learning new optical and structural characterization methods. Academic excellence, a professional approach to research, careful laboratory practice, and the ability to work independently are expected. The candidate must be able to communicate fluently in English, both orally and in writing, and should enjoy working in a collaborative and international research environment.

We offer a stimulating doctoral project on nanomaterials using state-of-the-art experimental techniques. The successful candidate will join a collaborative and international research group and will receive training in complementary optical and structural characterization methods. The project provides opportunities for collaboration with specialists in nanocrystal synthesis, theoretical modeling, and advanced microscopy, as well as participation in international conferences and the supervision of student research projects.

The position is based in the Department of Mechanical and Process Engineering (D-MAVT) at ETH Zurich’s central campus in Zurich, Switzerland. The student will have access to the laboratory’s optical microscopy and spectroscopy infrastructure, including advanced laser sources, spectrometers, detectors, and cryogenic equipment. The project will also benefit from ETH Zurich’s world-class electron-microscopy facilities and expertise. D-MAVT is an interdisciplinary department encompassing mechanical, process, chemical, and biomedical engineering, as well as robotics and control. ETH Zurich offers an outstanding scientific environment with extensive opportunities for collaboration across materials science, chemistry, physics, and engineering.

We look forward to receiving your online application with the following documents:

• A cover letter describing your motivation for the position, your relevant research experience, and your principal scientific achievements to date (max. two pages)
• A CV
• Diplomas and course transcripts
• Contact details for at least three academic or professional references

Further information about our laboratory can be found on our Website. Questions regarding the position should be directed to Prof. David J. Norris, [email protected] (no applications).

Please note that we exclusively accept applications submitted through our online application portal. Applications via email or postal services will not be considered.

We are recruiting a full-time doctoral candidate to develop theoretical and computational models of semiconductor nanocrystal growth, with an intended starting date on or after October 1, 2026.

The doctoral position is intended for four years at 100% employment and will be supervised by Prof. Dr. David J. Norris. The position is conditional upon admission to the doctoral program at ETH Zurich.

We would like to point out that the pre-selection is carried out by the responsible recruiters and not by artificial intelligence.