Structural and optical characterization of GaSb on Si (001) grown by Molecular Beam Epitaxy

Abstract

GaSb epilayers were grown on Si (001) using molecular beam epitaxy via AlSb quantum dots as an interfacial misfit (IMF) array between the Si substrates and GaSb epilayers. The effect of IMF array thickness, growth temperature and post annealing on the surface morphology, structural and optical properties of the GaSb on Si were investigated. Among five different IMF array thicknesses (5, 10, 20, 40 and 80 ML) that were used in this study, the best result was obtained from the sample with a 20 ML AlSb IMF array. Additionally, it was found that although the full width at half maximum (FWHM) and threading dislocation (TD) densities obtained from high resolution x-ray diffraction curves can be improved by increasing the growth temperature, a decrease in the photoluminescence (PL) signal and an increase in the surface roughness (RMS) emerged. On the other hand, the results indicate that by applying post annealing the GaSb epilayer crystal quality can be improved in terms of FWHM, TD density, PL signal or RMS depending on the post annealing temperature. By applying post annealing at 570 °C for 30 min we achieve a FWHM value of 260 arcsec for a 1 μm thick GaSb epilayer on Si (001) and improve the PL signal intensity without worsening the RMS value.

ULTRARAM: A Low‐Energy, High‐Endurance, Compound‐Semiconductor Memory on Silicon

“…[13,14,22] The large lattice mismatch between the Si substrate and the GaSb buffer of 12.3% is relieved by a periodic array of 90° interface misfit dislocations propagating laterally along the Si-III/V interface. [23] A two-temperature-step GaSb growth method [24] was used to reduce the density of vertically propagating threading dislocations (see Experimental Section for more details).…”

ULTRARAM™: a low-energy, high-endurance, compound-semiconductor memory on silicon

“…These islands reduce the diffusion length of Ga atoms during the initial growth of the subsequent 2-µm GaSb buffer, helping to promote two-dimensional epitaxy and preventing the formation of planar twinning defects 8,9,17 . The large lattice mismatch between the Si substrate and the GaSb buffer of 12.3% is relieved by a periodic array of 90˚ interface misfit dislocations propagating laterally along the Si-III/V interface 18 . A two-temperature-step GaSb growth method 19 was used to reduce the density of vertically propagating threading dislocations (see Methods section for more details).…”

Intrinsic point defects and the n - and p -type dopability of the narrow gap semiconductors GaSb and InSb

“…8,9 Due to favourable lattice matching, GaSb can be used as a substrate for a wide range of ternary and quaternary III-V compounds. [10][11][12][13] The spin-orbit interaction (SOI) has a strong effect on the valence band structure of both systems, [14][15][16] but is more pronounced in InSb, 17,18 which, combined with a large Landé g-factor (over 50), 19 has meant that InSb has attracted considerable attention in the field of Majorana physics. 20,21 Moreover, GaSb and InSb have both been demonstrated to incorporate N and Bi effectively, resulting in a reduction in band gap [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] in a similar manner to the more widely studied, GaAs-based dilute nitrides and bismides.…”