Complex thin films are a key enabler of a range of multiple multibillion Euro energy technologies - including energy efficient materials, energy generation and power electronics. Such different technologies share common metrology challenges related to quality, performance and reliability. More information at https://www.hymet.ptb.eu/
One of the major problems, which is currently limiting the state-of-the-art photovoltaic solar cells, is related to the material degradation under sun light. We study the possibility that the root cause for the degradation is related to the interaction of light with copper ions. Our approach could lead to a rather simple solution in avoiding power loss: implementing charge on the surface to attract the copper ions.
Black silicon absorbs light very efficienctly over a wide spectral range. The challenge of this material has been related to the surface passivation due to the increased surface area of the nanostructures. Our research is focused on the passivation of the black silicon by atomic layer deposition that allows very conformal coating.
Defects and impurities (e.g. oxygen, metals, dislocations, point defects) are most often harmful when present in semiconductor devices. With deep understanding of relevant defect reactions and gettering mechanisms, it is possible to tolerate the defects without affecting the device performance. Our studies include gettering e.g. by P/B diffusion, SiOx precipitates, Al layer, implantation. The applications can be either high purity silicon or solar grade / upgraded metallurgical silicon. Our research activities include also the development of characterization methods for defects, e.g. based on minority carrier lifetime.
Atomic layer deposition (ALD) technology has roots in Finland. In close collaboration with Beneq Oy, we study the fundamental passivation mechanisms of ALD thin films as well as develop the processes and equipment both in n-type and p-type cells.
Copper contacts have already taken place in microelectronics. Because of the cheaper price as compared to currently used silver, copper will most likely appear soon in commercial solar cells. Our silicon solar cell processing line includes copper metallization by sputtering or evaporation followed by electroplating. We study among other things the suitability of interconnecting ribbon to the copper contacts.
Meeting global cooling demand with photovoltaics during the 21st century
Stability of the surface passivation properties of atomic layer deposited aluminum oxide in damp heat conditions
Low-T anneal as cure for LeTID in Mc-Si PERC cells
Cast Monocrystalline Silicon: New Alternative for Micro- and Nano-electromechanical Systems
Dissociation and Formation Kinetics of Iron-Boron Pairs in Silicon after Phosphorus Implantation Gettering
Passivation of Detector‐Grade FZ‐Si with ALD‐Grown Aluminium Oxide
Effect of MACE Parameters on Electrical and Optical Properties of ALD Passivated Black Silicon
Efficient passivation of low-reflectance MACE black silicon
Low-temperature dark anneal as pre-treatment for LeTID in multicrystalline silicon
Observation of Crystalline Oxidized Silicon Phase
Associate Professor Hele Savin
Email: hele.savin at aalto.fi
Tel.: +358 50 5410 156
Department of Electronics and Nanoengineering
Aalto University School of Electrical Engineering
P.O. Box 13500, 00076 Aalto, Finland
Micronova, 4th floor, room 4156
Tietotie 3, 02150 Espoo