The optical properties of GaAsN system alloys have not been clarified, particularly for the localized level around the bottom of the conduction band induced by nitrogen atoms. Herein, the recombination mechanism is systematically investigated for heavily Be-doped p-type GaAsN using both continuous-wave (CW) and time-resolved (TR) photoluminescence (PL) characteristics, which is expected to be applied to devices such as a p+-n+ tunnel diode inserted into a multijunction solar cell composed of GaAs system alloys and as the base layer of a heterojunction bipolar transistor. The S-shape characteristic weakened with increasing hole concentration (p) in the CW-PL spectra of Be-doped GaAsN. Both short and long lifetimes were evaluated using TR-PL decay curves. Specifically, the long lifetime was distributed between 0.7 and 1 ns independent of temperature and p. This long lifetime corresponds to radiative recombination lifetime from a localized level, supporting that a localized level is formed in Be-doped GaAsN despite high p on the order of 1019 cm−3. Electrons are tightly bound at a localized level, equivalent to this long lifetime, whereas the electron lifetime decreases with increasing p, resulting in the S-shape characteristic vanishing in the temperature dependence of the CW-PL spectra for ultraheavily Be-doped GaAsN with p of 5 × 1019 cm−3. Moreover, this S-shape characteristic vanished in the temperature dependence of TR-PL spectra for moderately Be-doped GaAsN with p of 8 × 1018 cm−3, indicating that the density of states is limited for a localized level.

In this study, electron traps in dilute GaAsN are investigated using the temperature dependence of electron concentration (n) and mobility (μe) for annealed heavily Si-doped GaAsN. The temperature dependence of n and μe depends on the annealing temperature, indicating that electrons are excited to the conduction band only from deep electron traps for heavily Si-doped GaAsN annealed at 580 °C. However, they are excited to the conduction band from both the deep electron traps and the shallow Si donor level for heavily Si-doped GaAsN annealed at 550 °C. The depth of the deep electron traps from the bottom of the conduction band for heavily Si-doped GaAsN annealed at 550 °C is almost equal to heavily Si-doped GaAsN annealed at 580 °C. The results demonstrate that these deep electron traps are inherent in dilute GaAsN because similar deep electron traps are also observed for the as-grown Si-doped GaAsN.

In the originally published article, the following values were presented incorrectly: 1) The values of the Si impurity concentration ([Si]) and the electron concentration (n) are slightly erroneous for the heavily Si-doped GaAsN, which are described as 6 × 1019 cm–3 and 9 × 1018 cm–3, respectively. The correct values of them are 2 × 1019 cm–3 and 6 × 1018 cm–3, respectively. Figure 1 and 2 with the correct values are presented below. 2) The value of n is applied for the evaluation of electron effective mass (me*) in the paper. The correct values of the decreased energy of the bandgap narrowing (ΔEBGN) and the increased energy of the Burstein-Moss effect (Efn) are 120 meV and 140 meV instead of 140 meV and 160 meV, respectively. Consequently, for the heavily Si-doped GaAsN, the correct value of me* is 0.11m0 instead of 0.098m0, where m0 is the electron mass. Figure 2 with the correct value is presented below. 1 Figure (Figure presented.) PL spectra of heavily Si-doped GaAsN with [Si] of 2 × 1019 cm−3 and [N] of 0.6% as a function of temperature. Black arrows indicate PL peak energy on each PL spectrum. 2 Figure (Figure presented.) Temperature dependence of PL peak energy for heavily Si-doped GaAsN with [Si] of 2 × 1019 cm−3 and [N] of 0.6% and moderately Si-doped GaAsN with [Si] of 1 × 1018 cm−3 and [N] of 0.7%. The authors state that these errors do not change the scientific conclusions of the paper in any way and apologize for any confusion this may have caused.

The photoluminescence (PL) mechanism is discussed for heavily Si-doped GaAsN, and the evaluation method of electron effective mass (me*) is proposed using its PL peak energy. PL peak energy monotonically decreases as increasing temperature, so the S-shape characteristic is vanished for this heavily Si-doped GaAsN as opposed to moderately Si-doped GaAsN. This result shows that the dominant PL process is an optical transition from the Fermi energy to the top of valence band independent of temperature for this heavily Si-doped GaAsN, as with degenerate n-type GaAs. Because PL peak energy is expressed by the sum of bandgap energy, the increased energy of the Burstein–Moss effect, and the decreased energy of the bandgap narrowing, me* is calculated to be 0.098 m0 for this heavily Si-doped GaAsN with nitrogen composition of 0.6%, where m0 is the electron mass. This result agrees well with previous studies, meaning that the method for estimation of me is effective for dilute GaAsN.

The Si doping mechanism is systematically investigated in dilute nitride GaAsN grown by radio frequency plasma assisted molecular beam epitaxy (RF-MBE). We change growth temperature, Si impurity concentration ([Si]), and nitrogen composition ([N]). The relationship between Si activation ratio (α) and [N] are evaluated using X-ray diffraction (XRD) 2θ-ω and Hall effect measurement. As [N] in GaAsN increases, α drastically decreases, which is ascribed to mechanisms of inactive Si donors such as a cluster of Si and N at an As site ((Si-N) As ). We find that the main factor of inactive Si donors in GaAsN depends on both [Si] and [N].