Band gap and band offsets of GaNAsBi lattice matched to GaAs substrate

Abstract

In this paper, we calculate the band gap and the band discontinuities of a GaN y AsBi x structure lattice matched to GaAs substrate using the conduction and the valence band anticrossing models at the same time. The results obtained show a good agreement with experiment. The nitrogen and the bismuth concentrations leading to a wavelength emission of 1.55 µm have been determined (x = 3.5%, y = 2%). This structure shows a good electron confinement resulting in a high characteristic temperature.Keywords GaNAsBi · Band anticrossing · Band offset · Band gap · Lattice matched IntroductionTemperature insensitive long wavelength (1.3 and 1.55 µm) laser diodes are very important sources for optical fiber communication. However, the conventional InP-based system exhibits a relatively low characteristic temperature due to poor electron confinement. As a novel GaAs-based material system, GaInNAs-based lasers grown on GaAs substrates offer a number of advantages in comparison with current GaInAsP-based lasers grown on InP substrates. The GaInNAs/GaAs system has a larger conduction band discontinuity and therefore provides better electron confinement and characteristic temperature (Henini 2005;Aissat et al. 2008;Ng et al. 2005). Moreover, this system is compatible with the well developed GaAs/AlAs distributed Bragg reflectors for surface emitting sources. Nowadays, the GaInNAs/GaAs lasers present very competitive characteristics at 1.3 µm wavelength, but it remains difficult to obtain comparable performance at longer emission wavelengths. Extending the wavelength of operation to 1.55 µm in this alloy system dictates N and In concentrations exceeding 2% and 35%, respectively, resulting in considerable degradation of the structural and optical properties. With increasing nitrogen concentration, the optical quality of the material usually deteriorates significantly resulting in a higher threshold current density of

Non-stoichiometric GaAsBi/GaAs (100) molecular beam epitaxy growth

“…To reach the desired wavelengths of 1.3-1.6 mm for fibre based communication applications, work has been performed at the lower substrate temperatures of 280 1C at the expense of crystal quality [4]. The lattice matched quaternary GaN y As 1À xÀ y Bi x grown on GaAs can theoretically reach 1.55 mm for x¼3.5% and y¼2% [12]. The growth temperature in this work allows for flexible tuning of Bi composition (as shown in Fig.…”

Novel Dilute Bismide, Epitaxy, Physical Properties and Device Application

“…Differing from nitride alloys which mainly have a downward energy shift effect on CB, Bi mainly has an upward effect on VB [153]. Co-doping of both elements is predicted to have more freedom in adjusting bandgap of materials applicable from UV to IR optical range.…”

“…The interaction between these localized trap states and the host semiconductor band brings changes in the band structure. The VBAC model has been extensively used to study the band structures of the GaAs 1−x Bi x alloys [58,67,153,213,214]. Prediction has indicated that dilute bismide alloys are promising to realize the SO split energy ∆ SO exceeding the bandgap energy E g for suppressing non-radiative Auger recombination and IVBA [53].…”

Bismide-Based Photonic Devices for Near- and Mid-Infrared Applications

“…InGaAsBi is promising for near-and mid-infrared photonic devices operating in the wavelength range of 1.5-4 μm. A significant reduction of band gap due to the incorporation of Bi atoms in InGaAs can again be described using the relatively simple VBAC theory [1,4,31,32]. It treats the interaction of the two types of states, i.e., the extended VBM and the localized Bi state, as a perturbation.…”

“…For GaAsBi/GaAs ΔE C is smaller than both ΔE hh and ΔE lh . The incorporation of nitrogen in GaAs has been shown to lead to conduction BAC, creating a large ΔE c and hence a strong band gap reduction [31,32].…”