In collaboration with the Physics Department of Parma University, IMEM is developing the epitaxial deposition, characterization and device development based on gallium oxide (Ga2O3 ), an ultra-wide bandgap semiconductor (gap=4.7-5 eV). Gallium oxide is a rising star in the nowadays material research and is attracting a lot of interest in the scientific community.
Its properties make it an excellent candidate for the realization of very high power devices, with performances higher than that of SiC or GaN.
Its high bandgap makes it an ideal building block for solar blind sensor in the UV-C range.
Ga2O3 has different polytypes: the thermodynamically stable phase is the beta, commonly used to realize power device. However, its monoclinic lattice makes it difficult to handle and poses problems in cutting and in the anisotropy of electrical and optical properties. Alpha and epsilon phases, despite metastable, are interesting because they can be deposited on sapphire and has higher symmetry.
The possible applications of Ga2O3 are:
- Power devices for energy conversion and distribution (in photovoltaic or eolic fields, power handling in trains or ships, etc.)
- UV-C solar blind photodetectors for fire monitoring and revelation, engines (missiles, airplanes - security) corona discharge in high voltage systems.
Development of epsilon-Ga2O3 epitaxy
For the deposition of Ga2O3 layers we use a custom MOVPE reactor using trimenthylgallium ,water and silane for n-type doping. We can use nitrogen, helium, argon and hydrogen as carrier gases.
We directed the effort to the study of the epsilon phase of Ga2O3, less known. From 2015 our group has evidenced several peculiarities of this polymorph, describing for the first time the crystal structure at the nanoscale and studying the optical and electrical properties.
Ga2O3 for solar blind deep-UV sensing
Our group has demonstrated that epsilon Ga2O3 can be used to realized solar blind UV-C sensors.
S. Leone, R. Fornari, M. Bosi, V. Montedoro, L. Kirstea, P. Philipp Doering, F. Benkhelifa, M. Prescher, C. Manz, V. Polyakov, O. Ambacher
Epitaxial growth of GaN/Ga2O3 and Ga2O3/GaN heterostructures for novel high electron mobility transistors
Journal of Crystal Growth 534 (2020) 125511
F. Boschi, M. Bosi, T. Berzina, E. Buffagni, C. Ferrari, R. Fornari
Hetero-epitaxy of epsilon Ga2O3 layers by MOCVD and ALD
J. Cryst. Growth. 443 (2016)
F. Mezzadri, G. Calestani, F. Boschi, D. Delmonte, M. Bosi, R. Fornari
Crystal Structure and Ferroelectric Properties of ε-Ga2O3 Films Grown on (0001)-Sapphire
Inorg. Chem. 55 (2016) 12079
I. Cora, F. Mezzadri, F. Boschi, M. Bosi, M. Čaplovičová, G. Calestani, I. Dódony, B. Pécz, R. Fornari
The real structure of ε-Ga2O3 and its relation to κ-phase
CrystEngComm 19 (2017) 1509
R. Fornari, M. Pavesi, V. Montedoro, D. Klimm, F. Mezzadri, I. Cora, B. Pécz, F. Boschi, A. Parisini, A. Baraldi, C. Ferrari, E. Gombia, M. Bosi
Thermal stability of ε-Ga2O3 polymorph
Acta Materialia, 140 (2017) 411
M. Pavesi, F. Fabbri, F. Boschi, G. Piacentini, A. Baraldia, M.Bosi, E. Gombia, A. Parisini, R.Fornari
ε-Ga2O3 epilayers as a material for solar-blind UV photodetectors
Materials Chemistry and Physics 205 (2018) 502