Partner: P. Wojnar

Institute of Physics, Polish Academy of Sciences (PL)

Recent publications
1.Wojnar P., Zieliński M., Janik E., Zaleszczyk W., Wojciechowski T., Wojnar R., Szymura M., Kłopotowski Ł., Baczewski L.T., Pietruchik A., Wiater M., Kret S., Karczewski G., Wojtowicz T., Kossut J., Strain-induced energy gap variation in ZnTe/ZnMgTe core/shell nanowires, APPLIED PHYSICS LETTERS, ISSN: 0003-6951, DOI: 10.1063/1.4873355, Vol.104, pp.163111-1-5, 2014
Abstract:

Strain-induced changes of ZnTe energy gap in ZnTe/ZnMgTe core/shell nanowires arising from lattice mismatch between the core and the shell semiconductor are studied by means of optical methods. It is shown that the increase of the Mg content in the shell, as well as the increase of the shell thickness result in an effective redshift of the near band edge photoluminescence from ZnTe nanowire cores, which reflects directly the decrease of energy gap under tensile strain conditions. The conclusions are supported by theoretical calculations in terms of the valence force field model. The observed change of ZnTe energy gap can be as large as 120 meV with respect to the unstrained conditions and can be tuned in a continuous manner by adjusting shell parameters, which open a path towards an effective band gap engineering in these structures.

Keywords:

Nanowires, II-VI semiconductors, Magnesium, Band gap, Quantum effects

Affiliations:
Wojnar P.-Institute of Physics, Polish Academy of Sciences (PL)
Zieliński M.-other affiliation
Wiater M.-Institute of Physics, Polish Academy of Sciences (PL)
Kret S.-Institute of Physics, Polish Academy of Sciences (PL)
Karczewski G.-other affiliation
Wojtowicz T.-Institute of Physics, Polish Academy of Sciences (PL)
Kossut J.-Institute of Physics, Polish Academy of Sciences (PL)
Janik E.-other affiliation
Zaleszczyk W.-other affiliation
Wojciechowski T.-Institute of Physics, Polish Academy of Sciences (PL)
Wojnar R.-IPPT PAN
Szymura M.-other affiliation
Kłopotowski Ł.-other affiliation
Baczewski L.T.-Institute of Physics, Polish Academy of Sciences (PL)
Pietruchik A.-Institute of Physics, Polish Academy of Sciences (PL)
2.Wojnar R., Wojnar P., Kret S., Elastic State Induced Energy Gap Variation in ZnTe/ZnMgTe Core/Shell Nanowires, TECHNISCHE MECHANIK, ISSN: 0232-3869, Vol.34, pp.233-245, 2014
Abstract:

The zinc telluride (ZnTe) nanowires grown recently are covered with the ZnMgTe shell. As a result of addition of magnesium the ZnMgTe lattice is expanded with respect to pure ZnTe lattice. From the lattice mismatch between the ZnMgTe shell and ZnTe nanowire core the internal strain and stress are created. Depending on the shell thickness and the Mg content in the shell the optical emission exhibits a considerable energy shift. To estimate this effect, at least qualitatively, the elastic state of the nanowire is calculated.

An analysis of the state of strain and stress in the core-shell nanowire within linear elasticity, using an analogy with thermal stresses is presented, in the similar way as it is applied, e.g. in hygro-mechanics. The suitable system of the differential Lame-Navier’s type equations is derived, and its solution for the axially symmetric problem is given. The jump of stress at the core-shell boundary is determined.

Affiliations:
Wojnar R.-IPPT PAN
Wojnar P.-Institute of Physics, Polish Academy of Sciences (PL)
Kret S.-Institute of Physics, Polish Academy of Sciences (PL)