Institute of High Pressure Physics

Development of societies and the world economy requires novel sources of cheap and clean energy. The Earth natural resources will suffice for 50-60 years and their use is burdened with leaving a significant carbon footprint.

In the next Thursday UNIPRESS seminar, dr inż. Andrzej Morawski from our Institute, head of the Superconductors Laboratory, will address the issue of energy storage focusing on "green" energy obtained from hydrogen. He will present a new construction developed by his team - a double-walled high-pressure hydrogen tank. The solution provides high density of stored energy and can find its application for mobile vehicles or backyard hydrogen storage systems. The hydrogen stored under pressure has a much lower unit price than liquid hydrogen, but its density is only slightly lower.

The Seminar “Hydrogen storage technologies at Unipress. Project summary and outlook” will be held on Thursday, June 29, 2023 at 15:00 on Zoom platform. To get the link to join the seminar, please contact us at dyrekcja@unipress.waw.pl

Dear Ladies and Gentlemen,

We are pleased to invite you to the IHPP PAS Seminar on Nitride Semiconductors. The next presentation will be held in a hybrid mode – at the New Technologies seminar room, Al. Prymasa Tysiąclecia 98, and through Zoom platform (to get the link, please contact us at nitride_seminar@mail.unipress.waw.pl ).

The next seminar is scheduled on Monday 26.06.2023 at 14:00.

Speaker: Prof. Bernard Gil (Laboratoire Charles Coulomb, CNRS-Université de Montpellier)

Title: The Optical Properties of Various Polytypes of sp²-bonded Boron Nitride.

Abstract

Sincerely,

Tadeusz Suski
Piotr Perlin
Anna Kafar

Dear Ladies and Gentlemen,

We are pleased to invite you to the IHPP PAS Seminar on Nitride Semiconductors. The next presentation will be held in a hybrid mode – at the New Technologies seminar room, Al. Prymasa Tysiąclecia 98, and through Zoom platform (to get the link, please contact us at nitride_seminar@mail.unipress.waw.pl ).

The next seminar is scheduled on Monday 12.06.2023 at 14:00.

Speaker: dr inż. Paweł Prystawko (IHPP PAS, NL-12)

Title: Compensation control of n-type GaN using intrinsic Carbon from TMGa precursor in MOVPE growth for Vertical GaN Power Devices

Abstract:

There is intrinsic residual doping with carbon in MOVPE grown GaN due to presence of carbon in organic precursor chemicals TMG and TEG. Usually n-type layers and unintentionally doped layers grown in standard growth conditions result in carbon incorporation as high as 10^17cm-3. It has been demonstrated that, if carbon content approached silicon donor value, an abrupt drop of electron mobility is observed. We investigated non-standard growth conditions to promote fast methyl radical elimination with active hydrogen originating from decomposed ammonia and resulted in reduction of carbon doping. These are: high growth pressure, high temperature as well as control of supersaturation by means of high V/III group ratio. It allows to reduce residual carbon doping below 1 x 10^16cm-3.

Sincerely,

Tadeusz Suski
Piotr Perlin
Anna Kafar

Dear Ladies and Gentlemen,

We are pleased to invite you to the IHPP PAS Seminar on Nitride Semiconductors. The next presentation will be held in a hybrid mode – at the New Technologies seminar room, Al. Prymasa Tysiąclecia 98, and through Zoom platform (to get the link, please contact us at nitride_seminar@mail.unipress.waw.pl ).

The next seminar is scheduled on Monday 29.05.2023 at 13:00.

Speaker: dr inż. Joanna Moneta (IHPP PAS, NL-12)

Title: Peculiarities of the strain relaxation in InGaN layers

Abstract:

The idea of using relaxed InGaN layers as pseudo-substrates for the growth of InGaN-based devices has emerged in the last years. While most of approaches of gaining relaxed InGaN are based on the elastically relaxed layers obtained by preparation of compliant layer (e.g., porous GaN) and subsequent patterning, in our attempt we focus on InGaN layers relaxed plastically by the introduction of misfit dislocations. An understanding of the dislocation formation process which allows prediction and control of the properties of relaxed InGaN layers is essential for achieving good quality InGaN/GaN templates.
InGaN layers with indium content close to 20% deposited on various types of (0001)-GaN substrates were studied. The growth was carried out by either Molecular Beam Epitaxy (MBE) or Metalorganic Vapor Phase Epitaxy (MOVPE). Structural analysis was done by means of transmission electron microscopy, cathodoluminescence imaging, traditional X-ray diffractometry and full-field X-ray diffraction microscopy.
The seminar will discuss the mechanisms of misfit dislocations nucleation and glide and the influence of GaN-substrate misorientation on the strain relaxation process. The impact on the structural properties of InGaN/GaN templates will be addressed.

Sincerely,

Tadeusz Suski
Piotr Perlin
Anna Kafar