Localization effects and band gap of GaAsBi alloys

Abstract

The structural and optical properties of GaAs1−xBix alloys for x up to 0.108 have been investigated by high resolution X‐ray diffraction and photoluminescence (PL). At room temperature (RT), the PL intensity of the GaAs0.97Bi0.03 sample was found to be ∼300 times higher than a GaAs control sample grown at the same temperature (400 °C). PL measurements carried out at 10 K show that when excitation power, Pex was increased from 0.11 to 1140 W cm−2, the PL peak energy blue‐shifts by 80 meV while the full‐width‐at‐half‐maximum reduces from 115 to 63 meV. However, the PL peak emission energy becomes independent of the excitation power at RT. The results indicate the presence of localized energy states in the GaAs0.97Bi0.03 sample, which trap carriers at low temperatures and that the majority of the carriers become delocalized at RT. Furthermore, the temperature dependent PL also shows an S‐shape behavior, which is a signature of localization effects. A theoretical model, which was derived by solving a rate equation was employed. The model successfully reproduces the observed S‐shape behavior and the theory fits well with the experimental data. The RT band gap of GaAs1−xBix for x up to 0.108 has been plotted and compared with the literature.

Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application

“…In this case the holes have less time to thermalize down into the localized states before they recombine, so that the corresponding PL peak shifts higher in energy. The temperature dependent PL of GaAs 1−x Bi x alloys shows an S-shape behavior due to the localized states [218].…”

Optical and spin properties of localized and free excitons in GaBixAs1−x/GaAs multiple quantum wells

“…This effect can also be evidenced by measuring the light scattering with specific polarization geometries. [1][2][3][4][5][6][7][8][9][10] are their polarizations relative to crystal planes of samples. According to the Raman selection rules for crystals for zinc-blend structures, the LO peak is allowed in -z(y,y)z geometry and forbidden in z(x,y)-z.…”

“…III-V dilute bismide semiconductor material has attracted much attention in recent years due to its potential applications for near infrared wavelength photonics and spintronics [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. The incorporation of Bi has been shown to have a dramatic impact on the band structure of GaAs.…”

“…The incorporation of Bi has been shown to have a dramatic impact on the band structure of GaAs. A band gap reduction of around 90 meV per percent of Bi and a large increase of spin-orbit (SO) split-off energy have been observed [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. This increase of spin-orbit interaction could suppress the non-radiative Auger recombination processes that affect the efficiency of lasers in the near infrared; it is also very attractive for semiconductor spintronics.…”

Optical study of local strain related disordering in CVD-grown MoSe2 monolayers

“…This kind of behavior is typical for disordered samples where the shape of the low-energy side of the PL band is determined by the density of localized states function q(E) and the shape of high-energy side is mainly due to the temperature dependent distribution function f(E,T) of localized carriers. These localized states can be formed by potential fluctuations caused by a high concentration of charged defects, 29,30 by spatial variation of semiconductor alloy composition, 31,32 or by variation of quantum well and quantum dot properties. 33,34 In many cases, the q(E) function has a Gaussian shape, but other shapes are also encountered.…”