Institute of Physics of Materials AS CR, v. v. i. > Projects > Exploitation of surface phenomena for elimination of extended defects in semiconductor nanostructures

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Exploitation of surface phenomena for elimination of extended defects in semiconductor nanostructures

Anotace

Semiconductor films are often grown on lattice-mismatched substrates, which results in a high density of threading dislocations that reduce the efficiency of LEDs, laser diodes, and HEMT transistors. Existing theoretical models of III-nitrides assume a purely covalent description of bonds and ignore their strong ionic component. In addition, experiments focus on the consequences of the large-misfit epitaxy and not on the origin of nucleation of extended defects. In this project, we formulate a new empirical potential for the Ga-Al-N-Si system, which will allow not only the determination of equilibrium structures but also the calculations of charge states of extended defects. Optimization of the early stage of III-nitride growth in a layer-bylayer fashion by ALD (PLD) will enable manufacturing of high-quality AlN/Si{111} and GaN/Si {100} substrates for homoepitaxial growth by MOVPE. Studies of the structure, electrical and optical properties of the heterostructures thus obtained will allow identification of the optimal route to preparing films with low density of extended defects.