Ultrawide Bandgap Ga₂O₃ for Next Generation Deep-UV Sensing

Solar-blind deep-UV (λ < 280 nm) photodetectors enable key applications such as flame monitoring, sterilization process control, and label-free surface inspection. Gallium oxide (Ga₂O₃, E₉ ≈ 4.4–5.3 eV, depending on crystalline structure and doping) is an ultra-wide-bandgap semiconductor that stands out for its versatile deposition on diverse substrates. In particular, room-temperature sputtering delivers filter-free solar-blind response on sapphire, Si/SiO₂, glass, and even flexible substrates. This PhD will establish a CMOS-compatible Ga₂O₃ platform and demonstrate fast, low-dark-current photodiodes, culminating in a first micro-imager demonstrator with robustness in harsh environments and under radiation.

Topic

This PhD is primarily experimental in nature. The successful candidate will develop sputtered Ga₂O₃ thin films at conditions ranging from room temperature up to CMOS-compatible thermal budgets, running systematic studies of thickness, annealing, crystallinity and intentional doping to balance responsivity and response time. Next, Photodiodes will be fabricated and characterized. Optimized device stacks and DUV-transparent top contacts will be used to qualify photodiode performance and reliability under UV-C exposure and under harsh environmental conditions. Application-oriented demonstrators will include a flame detector and a first DUV imager for high-contrast pathogen/surface imaging. Device modeling will play a supporting role (compact models/TCAD or optical simulations as needed) to design device layout and interpret measurements; the core contribution remains materials/process integration and device prototyping. The candidate will work closely with imec experts in materials, device processing, and ROIC design to define and reach target figures of merit (dark current, rejection ratio, responsivity, bandwidth) and to chart a path to BEOL-compatible integration.

The candidate

You hold a master’s degree in semiconductor physics, electrical engineering, materials/nano-engineering, or a related field. You are motivated to dive into thin-film optoelectronic devices and are hands-on in the lab (PVD/sputtering, ALD, lithography, etching) with a creative approach to problem solving and data analysis. Experience with thin-film deposition techniques and/or optical and electrical characterization (I-V/C-V, spectral responsivity, temporal response) is a plus. You communicate clearly, enjoy teamwork in a multidisciplinary, multicultural environment, and are eager to present and discuss your results. Given the international character of imec, an excellent command of English is required.