MBE research group is a part of the Institute of High Pressure Physics Polish Academy of Sciences (IHPP PAS) "Unipress".
We focus on the development of blue and green light-emitting diodes (LEDs) and laser diodes (LDs) using plasma-assisted molecular beam epitaxy (PAMBE). We carry out the research on long-wavelength light emitters: implement improvements in structure design and optimize optical and electrical parameters of gallium nitride (GaN) based devices. We investigate crystal growth mechanisms on GaN surfaces of various polarity and crystallographic orientation. We fabricate and study nitride heterostructures with tunnel junction. We also study vertical heterojunction transistors n-p-n (GaN/InGaN/GaN) fabricated on GaN substrates using MBE.
We are pleased to inform that the article "Role of Metallic Adlayer in Limiting Ge Incorporation into GaN" has been published in Materials and is available online. It describes the doping of a GaN crystal with germanium using the MBE method and describes the role of the metallic layer on the surface during epitaxy.
for Dr. Marta Sawicka "For a special contribution to the development of Polish digital transformation in 2021 for research on lasers"
Foto. Mariusz Szachowski
Good understanding and reproducibility of the n-type GaN electrochemical etching (ECE) process made this technique an interesting method of controlling the refractive index of GaN layers by changing their porosity. However, in the case of p-type GaN, the lack of model and understanding of the process appeared to be a significant obstacle in the demonstration of p-type ECE GaN etching in a controlled manner. In the work of N. Fiuczek et al. "Electrochemical etching of p-type GaN using a tunnel junction for efficient hole injection", recently published in the prestigious journal Acta Materialia, the authors explain the p-type etching mechanism and show that the use of a tunnel junction allows for very effective injection of carriers needed for digestion.
The paper presents for the first time electrochemical etching of GaN layers doped with p-type at constant voltage and without the use of an external light source. Thanks to the use of a tunnel junction, homogeneous and perfectly controllable etching of GaN and InGaN layers doped with Mg was obtained. Interestingly, the voltage range for which porous layers were obtained was only ~ 0.4 V. The threshold etching voltages (2.2 V) and the voltages at which strong etching was obtained (2.4 V) are much lower than for n-type doped GaN layers with the same concentration of admixtures. The work also showed that the transport of holes in the material was not limited to 200 µm in-plane distance. Using the proposed model of etching of p-typical GaN layers, it was explained how this process takes place in the tunnel junction system used as a layer for injecting carriers into the etched layer.
Current list of our projects:
„Tunnel junction and its applications for GaN based optoelectronics”
"Monolithic integration of superconductors and semiconductors on nitride platform”
"Circumvention of piezoelectric fields in III-nitride heterostructures – a way towards solving the green gap problem"
"Nanoporous GaN – a new platform for realization of quantum structures"
"Influence of build-in piezoelectric fields on performance of nitride laser diodes"
"Monolithic bipolar junction transistor driving LED in group III nitrides material system"
"'Buried periodic Arrays of NANOchannels for single-frequency nitride lasers"
"Seizing the advantages of Nitrogen-polar GaN for III-nitride light emitters"
List of completed projects HERE
Video (only Polish language version) recorded in 2014 - “Patent na Patent”:
From this short video you can learn about Grzegorz Muzioł PhD thesis (4:10). He explains the role of InGaN laser diode waveguide design on the optical mode leakage to GaN substrate (5:08). You can hear Prof. Czesław Skierbiszewski tellinng about the properties and applications of gallium nitride (3:25), and Prof. Piotr Perlin (TopGaN CTO) stressing the importance of innovative research for polish hi-tech business (8:34).
Institute of High Pressure Physics
Polish Academy of Sciences "UNIPRESS"
MBE LAB location:
al. Prymasa Tysiąclecia 98
PKP Koło - tram stop
Obozowa - bus stop
+48 22 8760351 - office
+48 22 8760324 - lab