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1

Derivation of von Weizsäcker Equation Based οn Green-Gauss Theorem

100%

Romanowski Z., Krukowski S.

Acta Physica Polonica A

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2009

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vol. 115

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issue 3

653-655

EN

A simple and short derivation of von Weizsäcker equation for kinetic energy functional is presented. The derivation is based on the Green-Gauss theorem and is valid for one-electron systems. In the proof the asymptotic behavior of wave function for the finite systems was used. Two results important for kinetic energy functional evaluation are also derived as consequences of the Green-Gauss theorem.

2

Optimization of InGaN Laser Diodes Based on Numerical Simulations

81%

Sakowski K., Strak P., Krukowski S., Marcinkowski L.

Acta Physica Polonica A

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2016

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vol. 129

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issue 1a

A-33-A-35

EN

Simulations of blue and green laser diodes with InGaN quantum wells are presented. In this study, a particular emphasis on efficiency and optical power of the structures was placed. Effect of the aluminum content in an electron blocking layer on the electron overflow and efficiency is discussed. Substantial decrease of efficiency of laser diodes is reported for low aluminum levels. It is also shown that polarization charges existing in AlInGaN heterostructures grown on GaN polar direction and low ionization degree of magnesium acceptors lead to high resistance of these devices. These effects hinder the carriers from reaching an active region and consequently they impose high operating voltages.

3

The Application of High Pressure in Physics and Technology of III-V Nitrides

61%

Grzegory I., Leszczyński M., Krukowski S., Perlin P., Suski T., Porowski S.

Acta Physica Polonica A

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2001

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vol. 100

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issue Supplement

57-109

EN

Due to high bonding energy of N_2 molecule, the III-V semiconducting nitrides, especially GaN and InN require high N_2 pressure to be stable at high temperatures necessary for growth of high quality single crystals. Physical properties of GaN-Ga(l)-N_2 system are discussed in the paper. On the basis of the experimental equilibrium p-T-x data and the quantum-mechanical modeling of interaction of N_2 molecule with liquid Ga surface, the conditions for crystallization of GaN were established. The crystals obtained under high pressure are of the best structural quality, having dislocation density as low as 10-100 cm^{-2} which is several orders of magnitude better than in any other crystals of GaN. The method allows to grow both n-type substrate crystals for optoelectronics and highly resistive crystals for electronic applications. The physical properties of the pressure grown GaN measured to characterize both point defects and extended defects in the crystal lattice are discussed in the paper. A special attention is paid to the application of high pressure to reveal the nature of the point defects in the crystals and electric fields in GaN-based quantum structures. Due to their very high structural quality, the pressure grown crystals are excellent substrates for epitaxial growth of quantum structures. It opens new possibilities for optoelectronic devices, especially short wavelength high power lasers and efficient UV light emitting diodes. This is due to the strong reduction in dislocation densities in relation to existing structures (10^6-10^8 cm^{-2}) which are grown on strongly mismatched sapphire and SiC substrates. The experimental results on the epitaxial growth and physical properties of GaN-based device structures supporting above conclusions are discussed in the paper. The current development of blue laser technology in High Pressure Research Center is shortly reviewed.

4

Blue Laser on High N_2 Pressure-Grown Bulk GaN

32%

Grzegory I., Boćkowski M., Krukowski S., Łucznik B., Wróblewski M., Weyher J., Leszczyński M., Prystawko P., Czernecki R., Lehnert J., Nowak G., Perlin P., Teisseyre H., Purgał W., Krupczyński W., Suski T., Dmowski L., Litwin-Staszewska E., Skierbiszewski C., Łepkowski S., Porowski S.

Acta Physica Polonica A

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2001

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vol. 100

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issue Supplement

229-232

EN

In this note we report briefly on the details of pulsed-current operated "blue" laser diode, constructed in our laboratories, which utilizes bulk GaN substrate. As described in Ref. [1] the substrate GaN crystal was grown by HNPSG method, and the laser structure was deposited on the conducting substrate by MOCVD techniques (for the details see Sec. 2 and Sec. 4 of Ref.~[1], respectively).

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4 Acta Physica Polonica A

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4 Krukowski S.

2 Grzegory I.

2 Leszczyński M.

2 Perlin P.

2 Porowski S.

2 Suski T.

1 Boćkowski M.

1 Czernecki R.

1 Dmowski L.

1 Krupczyński W.

1 Lehnert J.

1 Litwin-Staszewska E.

1 Marcinkowski L.

1 Nowak G.

1 Prystawko P.

1 Purgał W.

1 Romanowski Z.

1 Sakowski K.

1 Skierbiszewski C.

1 Strak P.

1 Teisseyre H.

1 Weyher J.

1 Wróblewski M.

1 Łepkowski S.

1 Łucznik B.

Derivation of von Weizsäcker Equation Based οn Green-Gauss Theorem

Optimization of InGaN Laser Diodes Based on Numerical Simulations

The Application of High Pressure in Physics and Technology of III-V Nitrides

Blue Laser on High N_2 Pressure-Grown Bulk GaN