Contactless electroreflectance, photoluminescence and time-resolved photoluminescence of GaInNAs quantum wells obtained by the MBE method with N-irradiation

Abstract

The optical properties of GaInNAs quantum wells (QW) grown by molecular beam epitaxy with and without N-irradiation (i.e. grown by the classical method) were investigated by the contactless electroreflectance (CER), temperature-dependent photoluminescence (PL) and time-resolved PL (TRPL). From CER measurements it was concluded that one type of nitrogen nearest-neighbor environment (In-rich environment) is dominant for GaInNAs QWs grown with N-irradiation whereas various nitrogen environments are present for the reference GaInNAs QW (i.e. the sample obtained by the classical method). PL and TRPL measurements clearly show that the optical properties of GaInNAs QWs are affected mainly by the amount of the incorporated nitride atoms. It was observed that the PL decay time decreased from ∼200 to ∼40 ps when the nitrogen concentration is increased from 0.8 to 2.2%. In addition, the presence of As flux during N-irradiation reduces the amount of the incorporated nitrogen and simultaneously improves the optical quality of GaInNAs QWs (i.e. it weakens the carrier localization at low temperatures and improves the quantum efficiency of PL).

Optical properties of GaAsBi/GaAs quantum wells: Photoreflectance, photoluminescence and time-resolved photoluminescence study

“…The presence of localized states also has a significant influence on the dynamics of PL at low temperature causing a longer PL decay time on the low-energy side than on the high-energy side [31,32]. An example of the temporal evolution of the PL spectrum (i.e., streak image) taken at 12 K for GaAs 0.944 Bi 0.056 MQWs is shown in figure 7 and the detailed analysis of PL decays at different energies is presented in figure 8.…”

Dynamics of time-resolved photoluminescence in GaInNAs and GaNAsSb solar cells

“…Time-resolved photoluminescence (TRPL) using up-conversion technique [11] is commonly used for estimating carrier lifetimes of optoelectronic heterostructures and has been extensively used in connection with optimization of GaInNAs heterostructures [2,12-14]. However, most of the studies have been concerned with analyses of quantum wells [15]. Studies on GaInAsN epilayers have reported a wide variety of lifetimes in the range of 70 to 740 ps [8,16].…”

Inhomogeneous broadening of optical transitions observed in photoluminescence and modulated reflectance of polar and non-polar InGaN quantum wells

“…Absorption-like experiments such as electromodulated reflectance (ER) spectroscopy (i.e., photoreflectance, electroreflectance or contactless electroreflectance) together with photoluminescence (PL), which is an emission-like method, are applied to study the optical quality of QWs, [10][11][12] are used in this study. PL is sensitive to localized states, which are manifested mainly at low temperatures, and, therefore, the temperature-dependent PL measurements are performed in order to evaluate the scale of carrier localization in the investigated samples.…”