Events
Get a PhD in physics!!!
|
|
| Read more... |
New multilayer design of metal to p-type GaN contact Sunday, 07 September 2025 15:45 |
One of the most formidable barriers in development of nitride-based optoelectronic devices: laser diodes (LDs) and light emitting diodes (LEDs) is high resistance of the metal/p-type nitride contact. The present date solutions are mostly based on Ni/Au contact still they are far from satisfactory. The situation requires basic investigations of the contact nature and technical implementation of new designs. Researchers from IHPP PAS applied complex ab initio and drift-diffusion calculation to elucidate contact nature. The results obtained include:
These results were published in the paper in Electronics vol. 14, p. 3309 (2025): Fundamentals of Metal Contact to p-Type GaN—A New Multilayer Energy-Saving Design Konrad Sakowski, Cyprian Sobczak, Pawel Strak, Stanislaw Krukowski This study opens a new possibility of application of the new design by implantation formation of the low resistance electric contacts in the near future.
Unipress at IWUMD 2025Wednesday, 03 September 2025 18:15 |
The 8th International Workshop on Ultra-Wide Bandgap Materials and Devices (IWUMD 2025) will be organized on September 21-24, 2025 in Wrocław, Poland. It will summarize and discuss the latest advances in wide bandgap semiconductor technologies. Institute of High Pressure Physics PAS will contribute with an oral presentation of Bohdan Sadovyi “Characterization of hBN Crystals Grown from Pure Ni-Based Solution at 1.5 kbar N₂ Pressure via Application-Focused Testing” and poster presentation of Robert Czernecki “UVA laser with a thick single AlInGaN quantum well”. Detailed program and all other information about the IWUMD 2025 can be found here: https://iwumd2025.pwr.edu.pl/
Two oral presentations from Unipress at ICDS-33Thursday, 28 August 2025 10:01 |
We are pleased to inform you that our colleague from laboratory NL-12, Dr. Piotr Kruszewski, will represent our Institute at the ICDS-33 conference - 33rd International Conference on Defects in Semiconductors, which will take place from September 14 to 19, 2025, in Shanghai, China. ICDS conference is one of the most prestigious international conferences dedicated to defect research in semiconductors, and the first conference of this series was initiated in 1959 in Gatlinburg, Tennessee, USA. A significant honor for our Institute is the fact that Dr. Piotr Kruszewski will deliver two oral presentations in Shanghai. The first one is focused on defect studies in AlxGa1-xN layers and is titled "On the origin of the electrically active defects E1 and E3 in GaN and dilute AlxGa1-xN films grown on Ammono-GaN substrates" while the second presentation addresses defects in gallium oxide (Ga2O3) and the influence of an electric field on the defect properties Ec-0.18 eV in crystals grown by the Czochralski method. The full title of this paper is "The electric field influence on EC-0.18 eV electron trap level in (100)-oriented β-Ga2O3 crystals grown by the Czochralski method" More information about the conference, as well as the detailed program, can be found at https://www.icds2025.org/
|
Institute Thursday SeminarFriday, 05 September 2025 12:29 |
Would you like to know why the conductivity in AlN, AlGaN and GaN sometimes remains limited despite intentional doping? And how to find the cause of electrical compensation distinguishing between acceptor impurities, native vacancies, and amphoteric donors? During the next Unipress Thursday Seminar, Dr. Igor Prozheev from the University of Helsinki, Finland will present advanced experimental and theoretical methods, such as ion implantation and positron annihilation combined with DFT calculations, to reveal how these point defects impact the performance of opto- and power electronic devices. The talk tile is „The Alchemy of Nitrides: from Experiment to Theory”. Join us live in the Institute of High Pressure Physics, al. Prymasa Tysiąclecia 98, Warsaw, seminar room on II floor, or online via Zoom platform on Thursday, Spetember 25, 2025 at 3:00 pm. To get the link to Zoom meeting, please contact us at dyrekcja@unipress.waw.pl Abstract of the talk is here.
Beryllium in GaN – a new insight into acceptor natureWednesday, 03 September 2025 18:04 |
Doping Gallium Nitride (GaN) with beryllium has attracted much attention due to its potential applications in electronics and optoelectronics. Early studies suggested Be acceptors to have a lower ionization energy than the commonly used magnesium (Mg). However, previous attempts mostly lead to fabrication of semi-insulating material, due to a self-compensation effect – the tendency of Be atoms to occupy interstitial positions in GaN lattice (instead of substitution ones), forming competing donor defects. Recent studies indicate that Be may have a more complex dual nature: acting as a shallow acceptor or as a deeper polaronic acceptor. Research carried out by the Institute of High Pressure Physics PAS, in collaboration with Virginia Commonwealth University and the University at Albany (USA), published in the Journal of Applied Physics, confirmed this hypothesis. Hall effect measurements on GaN:Be layers showed p-type conductivity without overcompensation by donors, with an acceptor activation energy of ~0.40 eV. These results suggest that effective p-type doping of GaN with Be is more challenging than previously expected. The research was funded by the National Science Centre, Poland (grant no. 2020/37/B/ST5/03746). More details can be found in the following publication: M. Zając et al., Journal of Applied Physics 138, 095705 (2025). https://doi.org/10.1063/5.0283055.
Experimental pT-3/2 vs inverse temperature dependence of GaN:Be epitaxial layers of various Be content. Solid lines represent fits yielding deep Be acceptor level at T=0. |
Links |
