Pressure-Driven Reordering of Valence Band States in AlGaN/AlN Quantum Wells

• Authors: S. Łepkowski , W. Bardyszewski
• Languages of publication: EN

Abstracts

EN

We study theoretically the influence of external hydrostatic pressure on the valence band structure in [0001]-oriented Al_{x}Ga_{1-x}N/AlN quantum wells used in deep-ultraviolet light emitting devices. The calculations performed using the multi-band k·p method with excitonic effects show that for Al_{x}Ga_{1-x}N/AlN quantum wells with x = 0.7 and quantum well width of 1.5 nm, reordering of the topmost valence subbands having different symmetries occurs with increasing pressure. In these structures, at low pressure values the topmost valence level is of Γp_9 symmetry whereas it changes to the Γp_7 state for pressures about 2.5 GPa. We also find that the excitonic effects increase the critical value of pressure at which the change in the polarization of the emitted light occurs to 7 GPa. This behavior is opposite to the pressure-dependent reordering of the topmost valence band states in thin GaN/AlGaN quantum wells which occurs from Γp_7 to Γp_9 states.

Keywords

EN

78.55.Cr; 78.67.De; 62.50.-p

Discipline

• 78.55.Cr: III-V semiconductors
• 78.67.De: Quantum wells
• 62.50.-p: High-pressure effects in solids and liquids(for high pressure apparatus and techniques, see 07.35.+k; for high-pressure behavior of rocks and minerals, see 91.60.Gf; for pressure treatments, see 81.40.Vw in materials science; for effects of pressure on superconducting transition temperature, see 74.62.Fj)

• Journal: Acta Physica Polonica A
• Year: 2012
• Volume: 122
• Issue: 6
• Pages: 1029-1030

Dates

published

2012-12

Contributors

author

S. Łepkowski

• Institute of High Pressure Physics, "Unipress", Polish Academy of Sciences, Sokołowska 29/37, 01-142 Warszawa, Poland

author

W. Bardyszewski

• Institute of Theoretical Physics, Faculty of Physics, University of Warsaw, Hoża 69, 00-681 Warszawa, Poland

References

• 1. K.B. Nam, J. Li, M.L. Nakarmi, J.Y. Lin, H.X. Jiang, Appl. Phys. Lett. 84, 5264 (2004)
• 2. R.G. Banal, M. Funato, Y. Kawakami, Phys. Rev. B 79, 121308 (2009)
• 3. W. Bardyszewski, S.P. Łepkowski, Phys. Rev. B 85, 035318 (2012)
• 4. T.K. Sharma, D. Naveh, E. Towe, Phys. Rev. B 84, 035305 (2011)

Identifiers

DOI

10.12693/APhysPolA.122.1029