Nanoscale physics

Quantum wells delta-doped to the center with background doping in barriers
Demediuk, R.1, Tulupenko, V.1,4, Akimov, V.1,2, Tiutiunnyk, A. 3, 
Duque, C.1,4, Sushchenko, D.1, Fomina, O.1, Laroze, D. 3
1 Physics Department, Donbas State Engineering Academy, Academichna str., 72, Kramatorsk-84313, Donetsk reg., Ukraine.
E-mail: demediuk.roman@gmail.com
2 Facultad de Ciencias Basicas, Universidad de Medellín, Grupo de Materia Condensada-UdeA, Universidad de Antioquia, Medellín, Colombia.
3 Instituto de Alta Investigación, CEDENNA, Universidad de Tarapacá, Arica, Chile.
4 Grupo de Materia Condensada-UdeA, Universidad de Antioquia, Medellin, Colombia.

Previously we proposed the idea of a novel design of tunable optical device based on intersubband transitions within quantum well and grounded it numerically for Si/Ge heterostructure [1]. The tunability is provided by altering the ionization degree of the Phosphorus delta-layer within the well and subsequent distortion of potential profile of the well that leads to the change of transition energies and working frequencies of the device. To calculate energy characteristics of the structure we elaborated a numerical method based on the self-consistent scheme by including impurity binding energy with a Vinter technique [2] as a part of iteration. 
Here we verify the viability of the proposed design by including sparce background impurity to the barriers of the structure in the approximation of a single well with infinite barriers. We have modified the numerical procedure to account for the infinite barriers and altered calculation of Fermi energy. 
Calculations for the background impurity up to 1016 cm-3 showed that the tuning effect remains stable qualitatively with some notable quantitative changes for higher concentrations. The binding energy of impurity within the well demonstrated changes about two times depending on the ionization degree of the delta level.
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1.	V. Tulupenko, A. Abramov, Ya. Belichenko, V. Akimov,et al., The influence of the ionized impurity delta-layer potential in the quantum well on impurity binding energy // Journ Appl Phys.-2011.-109.- p. 064303. 
2.	B. Vinter, Influence of charged impurities on Si inversion-layer electrons // Phys. Rev. B.-1982.-26.- p. 6808.