A. Fuchsberger, L. Wind, M. Sistani, R. Behrle, D. Nazzari, J. Aberl, E. Prado Navarete, L. Vukŭsić, M. Brehm, P. Schweizer, L. Vogl, X. Maeder, W. M. Weber, Reconfigurable Field-Effect Transistor Technology via Heterogeneous Integration of SiGe with Crystalline Al Contacts, opens an external URL in a new window, Advanced Electronic Materials, aelm 202201259 (2023)

In collaboration with the Weber group at TU Vienna and the EMPA in Switzerland, we have demonstrated top-down fabricated SiGe-based reconfigurable transistors comprised of a vertical Si-Si_0.67Ge_0.33 heterostructure enabling the envisioned high and symmetric on-currents of both n- and p-type operation.
Our MBE growth of highly supersaturated and Ge-rich films, performed at ultra-low temperatures and excellent vacuum conditions, provides the base for this planar and scalable technology.

Following the biennial cycle, the 22^nd International Winterschool on New Developments in Solid State Physics should have taken place in February 2022, which would have been a nice coincidence of numbers, if the Covid-19 pandemic had not prevented us from holding the conference then.

Shortly before the Corona outbreak (the first 2 cases in Austria were confirmed on 25 February 2020), the 21^st Winterschool had very successfully taken place from 23-28 February 2020, with 220 participants from 16 different countries, mainly European (Austria, Germany, Switzerland, Sweden, Finland, Italy, France, Czech Republic, Netherlands, UK), but also from USA, Australia, Canada and Brasil.

So now after 3 years, we are looking forward to the upcoming Winterschool!

In a collaboration with the Weber group at TU Vienna and the EMPA in Switzerland, we have shown the potential of epitaxial SiGe nanosheets grown with MBE at ultra-low temperatures and exscellent vacuum conditions.
Aluminum/SiGe exchange enables the fabrication of advanced nanoelectronic devices

L Wind, M Sistani, R Böckle, J Smoliner, L Vukŭsić, J Aberl, M Brehm, P. Schweizer, X. Maeder, J. Michler, F. Fournel, J.‐M. Hartmann, W. M Weber,
Composition Dependent Electrical Transport in Si1−xGex Nanosheets with Monolithic Single‐Elementary Al Contacts, opens an external URL in a new window
Small 18 (44), 2204178 (2022)

The GADEST-19 conference was devoted to semiconductor defect physics, materials science and device technology and focuses on both fundamental as well as technological aspects of defects, growth, processing and modelling of electronic materials and devices, ranging from microelectronics to photovoltaics.

Many exciting presentations and fruitful discussions in the beautiful city of Mondsee

Link to the GADEST Homepage

The GADEST-19 conference is approaching.

The GADEST conference series provides a forum for interaction between scientists and engineers engaged in the field of semiconductor defect physics, materials science and device technology. The conference is focused on fundamental aspects as well as technological problems associated with defects in electronic materials and devices ranging from microelectronics to photovoltaics. The topics can be summarized into three main categories:

1) The first category includes the optimization of Si as host material for improved electronic and photovoltaic device function. It spans from crystal growth, defect and impurity engineering, stress engineering, source-drain and channel engineering, optimization of doping profiles, to interface and gate engineering.

2) The second category involves the design of heterosystems including material components other than Si as host material for improved and new device functionalities. Main fields are high frequency Si/Ge-electronics on Si, high mobility channel materials, heterogeneously integrated (III – V / Si) photonics, heavily doped carbon nanotubes as contacts.

3) The third category includes basic research on device physics, point defects, getter effects, and extended defects. In the center of interest are results obtained by spectroscopic methods, advanced measurement and detection methods, ab initio calculations and predictive modeling.

Of course, the topics mentioned under the categories are not exhaustive. Any contribution fitting into the focus of the conference is welcome.

Growth of Ge-rich nanolayers exceeding expected critical thickness limits while maintaining excellent epitaxial qualty.
Low temperature growth at excellent growth pressures necessary

A Salomon, J Aberl, L Vukušić, M Hauser, T Fromherz, M Brehm
Relaxation delay of Ge‐rich epitaxial SiGe films on Si (001), opens an external URL in a new window
physica status solidi (a) 219, 2200154

First demonstration of Ge hutwires grown on silicon on insulator substrates.
We found that hutwires of suitable length and density can only be grown within a very narrow range of growth parameters.
Every °C counts!

J Aberl, L Vukušić, F Fournel, JM Hartmann, M Brehm
Epitaxial Growth of Planar Hutwires on Silicon‐on‐Insulator Substrates, opens an external URL in a new window
physica status solidi (a) 219 (17), 2200145

The Center for Surface and Nanoanalytics (Zona) developed a method for temperature-dependent transmission electron microscopy experiments.
Investigate the thermal limits of your samples and devices

A Minenkov, N Šantić, T Truglas, J Aberl, L Vukušić, M Brehm, H Groiss
Advanced preparation of plan-view specimens on a MEMS chip for in situ TEM heating experiments, opens an external URL in a new window
MRS bulletin 47 (4), 359-370

We intentionally let quantum dot nanostructures merge to enhance the strain and thus their light emission properties

J Schuster, J Aberl, L Vukušić, L Spindlberger, H Groiss, T Fromherz, M Brehm, F Schäffler
Photoluminescence enhancement by deterministically site-controlled, vertically stacked SiGe quantum dots, opens an external URL in a new window
Scientific Reports 11 (1), 20597

The book chapter discusses the state-of-the-art of Si-based light sources with special emphasis on defect-enhanced quantum dots

M Brehm
Light-emission from ion-implanted group-IV nanostructures, opens an external URL in a new window
Silicon Photonics IV: Innovative Frontiers, 67-103 (2021)

The indirect semiconductor Ge can be made a direct bandgap light emitter by adding split-interstitial defects.
This article discusses the properties of defect-enhanced quantum dots from a first-principle pont of view.

 

F Murphy-Armando, M Brehm, P Steindl, MT Lusk, T Fromherz, K Schwarz, P Blaha
Light emission from direct band gap germanium containing split-interstitial defects, opens an external URL in a new window
Physical Review B 103 (8), 085310 (2021)

We applyed an advanced hydrogenation process, recently developed in photovoltaic research for the passivation of performance-limiting defects in Si solar cells to increase the room-temperature light emission from Ge/Si nanostructures. This technique efficiently passivates nonradiative recombination channels induced by defects in the SI matrix of the Si/SiO2 interface

L Spindlberger, M Kim, J Aberl, T Fromherz, F Schäffler, F Fournel, J.-M. Hartmann, B. Hallam, M. Brehm
Advanced hydrogenation process applied on Ge on Si quantum dots for enhanced light emission, opens an external URL in a new window
Applied Physics Letters 118 (8), 083104 (2021)

START prize of the Austrian Science Funds FWF

Funding: 1.200.000 €

Silicon light emitters based on defectenhanced quantum dots

Image: with Federal Minister Mag. Dr. Iris Rauskala and Prof. Dr. Klement Tockner, FWF president

F. Hackl, M. Grydlik, Petr Klenovský, F. Schäffler, T. Fromherz, M. Brehm

Quantum Dots: Assessing Carrier Recombination Processes in Type‐II SiGe/Si(001) Quantum Dots, opens an external URL in a new window

Ann. Phys. 6/2019, 1970025, opens an external URL in a new window

Different recombination paths can strongly influence the optical properties of quantum dots. The green, red, and blue surfaces indicate the probability densities of heavy‐hole, Δ_z, and Δ_xy electron wave‐functions, respectively, as discussed in article number 1800259, opens an external URL in a new window by Florian Hackl, Thomas Fromherz, Moritz Brehm, and co‐workers.

by Florian Hackl, Martyna Grydlik, Petr Klenovský, Friedrich Schäffler, Thomas Fromherz, and Moritz Brehm
was published in the venerable journal Annalen der Physik,

We have identified different recombination paths in Ge/Si quantum dots that contribute significantly to luminescence line broadening in these structures. Using time-resolved spectroscopy, we highlight that the various carrier transition paths are differently influenced by non-radiative carrier recombination such as e.g. Auger-recombination.

by H. Groiss, L. Spindlberger, P. Oberhumer, F. Schäffler, T. Fromherz, M. Grydlik and M. Brehm,
has been chosen for the 2017 Semiconductor Science and Technology (SST) highlight collection.

Our topical review "Site-controlled and advanced epitaxial Ge/Si quantum dots: fabrication, properties, and applications" was included in the Highlights of Nanotechnology 2017, opens an external URL in a new window

This collection includes outstanding articles and Topical Reviews published in the journal during 2017. These articles were selected on the basis of a range of criteria including referee endorsements, presentation of outstanding research and popularity with our online readership.
The articles will be free to read until the end of December 2018. Our article is open access anyways, thanks to Funding from the FWF.

The article: Room-Temperature Group-IV LED Based on Defect-Enhanced Ge Quantum Dots  can be accessed here: