Time-Resolved Photoluminescence in Heterostructures with InGaAs:Cr/GaAs Quantum Wells
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INTERNATIONAL SYMPOSIUM “NANOPHYSICS AND NANOELECTRONICS”, NIZHNY NOVGOROD, MARCH 10–13, 2020
Time-Resolved Photoluminescence in Heterostructures with InGaAs:Cr/GaAs Quantum Wells M. V. Dorokhina,*, P. B. Deminaa, Yu. A. Danilova, O. V. Vikhrovaa, Yu. M. Kuznetsova, M. V. Ved’a, F. Iikawab, and M. A. G. Balantac a Physical
Technical Research Institute, Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, 603950 Russia b Instituto de Fisica “Gleb Wataghin”, UNICAMP, Campinas, SP, Brazil c Universidade Federal de Uberlândia-ICENP, Ituiutaba, MG, Brazil *e-mail: [email protected] Received April 15, 2020; revised April 21, 2020; accepted April 21, 2020
Abstract—The results of studies of the time-resolved photoluminescence in semiconductor heterostructures containing two noninteracting InGaAs quantum wells in a GaAs matrix are reported. One of the quantum wells was undoped, and the other was uniformly doped with chromium atoms (InGaAs:Cr). It was shown that the introduction of Cr had a profound effect on the recombination lifetime of charge carriers in quantum wells. The change in the photoluminescence intensity after excitation cannot be described by a monoexponential decay function, which is attributed to a change in the built-in electric field of the surface barrier in the quantum wells because of screening by photoexcited charge carriers. Keywords: photoluminescence, heterostructures, quantum wells, Cr impurity DOI: 10.1134/S1063782620100061
1. INTRODUCTION The doping of structures based on III–V compounds with 3d transition elements (Mn, Cr) is conducted for the purpose of controlling various properties of semiconductor materials. First of all the fabrication of ferromagnetic semiconductor layers is of interest. As a rule, this can be implemented only at high concentrations of the introduced magnetic impurity (much higher than the solubility limit) [1, 2]. At the same time, the creation of spintronic devices assumes the use of semiconductor materials with a rather long spin lifetime, separated from ferromagnetic layers. In solving this problem, it was shown [3, 4] that the introduction of transition elements into heterostructures based on III–V semiconductors provided a means for controlling spin-relaxation processes. For example, doping of GaAs with Mn atoms to the concentration NMn ≈ 8 × 1017 cm–3 (below the solubility limit ~8 × 1019 cm–3) results in a substantial increase in the electron spin-relaxation time [3]. In [4], it was established that the diffusion entry of Mn atoms into GaAs/AlGaAs quantum wells (QWs) resulted in an increase in the spin lifetime as well. Finally, the doping of III–V semiconductors with atoms of transition elements is considered as a traditional method for controlling the recombination characteristics, specifically, the relation between the radia-
tive and nonradiative recombination times in structures [5, 6]. At present the subject of interest includes the analysis of all of the above-mentioned three applications of quantum-confined heterostructures, which are ex
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