GaSb-based solar cells for multi-junction integration on Si substrates

Abstract

We report on the first single-junction GaSb solar cell epitaxially grown on a Si substrate. A control stand-alone GaSb solar cell was primarily fabricated, which demonstrated a 5.90% efficiency (AM1.5G). The preparation, growth and manufacturing procedures were then adapted to create the GaSb-on-Si solar cell. The hybrid device resulted in a degraded efficiency for which comparison between experimental and simulated data revealed dominant non-radiative recombination processes. Material and electrical characterization also highlighted the impact of anti-phase domains and boundaries and threading dislocation density on the shunt resistance of the cell. Nevertheless, the GaSb-on-Si cell performance is close to recent results on the integration of GaSb solar cells on GaAs, despite a much larger lattice mismatch (12% vs 8%). Routes for improvement, concerning the material quality and cell structure, are proposed. This work lays the foundations of a GaSb-based multi-junction solar cell monolithically integrated on Si.

Simulation aided design of a high efficient GaSb based single-junction solar cell

“…This is followed successively by a 3 μm thick n-type Base layer with concentration 10 17 cm −3 , and a p-type Emitter having 100 nm of thickness and carrier concentration of 10 19 cm −3 . Finally, the whole is sheltered by a wide band gap p-doped AlGaAsSb Window layer having 10 nm of thickness and 3310 19 cm −3 of carrier concentration.…”

“…However, this has no effect on significance of the obtained results as it will be seen in the next section by considering a more accurate quadratic regression model. Taking into account the results offered by the preliminary simulations, the least influential design parameters were fixed at the following values: Bt ¼ 4μm, BSFd ¼ 1:5319 19 cm −3 and BSFt ¼ 0:035μm.…”

Development and application of quasi-planar InGaAsSb p-B-n devices for spectroscopic sensing

“…Through alloying, quaternary materials such as InGaAsSb are produced, which allows the leakage and cut-off balance to be finely tuned to an application. InGaAsSb lattice matched to GaSb can have a cut-off wavelength up to 4.9 μm, which extends beyond the binary GaSb which is limited to a cut-off of 1.7 μm 1 . Within the InGaAsSb cut-off range are the absorption fingerprints of substances such as glucose 2 , acetone 3 and CO2 4 , making this material prime for high impact applications.…”

Band gap engineering by cationic substitution in Sn(Zr1−xTix)Se3 alloy for bottom sub-cell application in solar cells

“…There are only a few well-studied materials (not alloys) that have optimal E g for the bottom sub-cell in Si-based 3J devices: Ge ( E g = 0.67 eV) 6 and GaSb ( E g = 0.72 eV). 7 Generally, it is more common to employ alloys and fine-tune E g for the targeted region by adjusting the chemical composition. For example, Hg 1− x Cd x Te 8 and In 1− x Ga x As 9 alloy systems can cover a very wide spectral range in the infrared region (Fig.…”