2011/11/21 by Kanchana Sivalertporn, K. Sivalertporn, Leonidas Mouchliadis +5 · 6 citations
Engineering · Physics and Astronomy · #Quantum and electron transport phenomena #Semiconductor Lasers and Optical Devices #Semiconductor Quantum Structures and Devices #cond-mat.other
paper · pdf · doi:10.1103/physrevb.85.045207
published as Phys. Rev. B 85, 045207 (2012) · 12 pages, 11 figures
arxiv created 2011/11/21 · openalex publication_date 2012/01/17 · arxiv updated 2012/05/15 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/31
An accurate calculation of the exciton ground and excited states in AlGaAs and InGaAs coupled quantum wells (CQWs) in an external electric field is presented. An efficient and straightforward algorithm of solving the Schr"odinger equation in real space has been developed and exciton binding energies, oscillator strengths, lifetimes, and absorption spectra are calculated for applied electric fields up to 100 kV/cm. It is found that in a symmetric 8--4--8-nm GaAs/Al0.33Ga0.67As CQW structure, the ground state of the system switches from direct to indirect exciton at approximately 5 kV/cm with dramatic changes of its binding energy and oscillator strength while the bright excited direct-exciton state remains almost unaffected. It is shown that the excitonic lifetime is dominated either by the radiative recombination or by tunneling processes at small/large values of the electric field, respectively. The calculated lifetime of the exciton ground state as a function of the bias voltage is in a quantitative agreement with low-temperature photoluminescence measurements. We have also made freely available a numerical code for calculation of the optical properties of direct and indirect excitons in CQWs in an electric field.