Effect of Bi surfactant on atomic ordering of GaAsSb

Abstract

The addition of small quantities of a Bi surfactant is shown to have dramatic effects on the microstructure of GaAsSb alloys grown by organometallic vapor phase epitaxy (OMVPE). Epilayers grown without Bi show weak atomic ordering in plan-view selective area electron diffraction measurements, with periodicity of three or six times the [110] lattice spacing as previously reported. The addition of Bi at a ratio of 1% Bi∕Ga to the gas flow results in the appearance of strong CuAu and chalcopyrite ordering, as determined from electron diffraction measurements in both undoped, and heavily carbon doped layers. High-resolution, transmission electron microscopy lattice images clearly show the coexistence of {100}, {210} ordered and disordered structures with domain sizes of ∼10–20nm. Photoluminescence shows no band gap changes in GaAsSb samples with and without {100} and {210} ordering.

Optical and electrical characterization of OMVPE-grown AlGaAsSb epitaxial layers on InP substrates

“…It is worth noting that other authors have seen fairly large discrepancies of up to 0.2 eV in the PL energies compared with predictions obtained using tabulated values of the bowing parameters [15]. We have also performed TEM measurements on these samples, which showed ordering in these quaternary material similar to the Cu-Au type observed in GaAsSb [16,17]. Recent PL measurements on GaAsSb ternary alloys indicated that the presence or absence of strong Cu-Au ordering had no effect on the PL energies [17].…”

“…We have also performed TEM measurements on these samples, which showed ordering in these quaternary material similar to the Cu-Au type observed in GaAsSb [16,17]. Recent PL measurements on GaAsSb ternary alloys indicated that the presence or absence of strong Cu-Au ordering had no effect on the PL energies [17].…”

Microstructure of ordered nanodomains induced by Bi surfactant in OMVPE-grown GaAsSb

“…We have also observed weak three-fold and six-fold ordering along [1 1 0] which correlates with increased bulk resistivity along the [1 1 0] direction in OMVPE-grown GaAsSb [11]. In a previous paper, we reported that Bi can be used as a surfactant to produce dramatic changes in the ordering microstructure of GaAsSb grown on exact (0 0 1) InP surface by OMVPE [12]. strong CuAu and CH orderings similar to those originally reported in GaAsSb growth on 31 offcut (0 0 1) InP [3].…”

Atomic ordering in GaAsSb (001) grown by metalorganic vapor phase epitaxy

“…The effect of Bi surfactant was briefly discussed in an earlier paper [8]. The strongest ordering effects were observed using the SH1 chamber as shown in Fig.…”

“…Atomic ordering of III-V semiconductor alloys has been widely studied in the past two decades [1][2][3][4][5][6][7][8]. The most common ordered phase is the so-called CuPt variant in which an alloy compound semiconductor, usually grown by either molecular beam epitaxy (MBE) or metalorganic vapor phase epitaxy (MOVPE), spontaneously forms ordered superlattices aligned along the (111)B planes.…”