High-efficiency Al0.3Ga0.7As solar cells grown by molecular beam epitaxy

Abstract

This letter reports the growth of high-efficiency Al0.3Ga0.7As solar cells by molecular beam epitaxy. As the growth temperature increases from 650 to 750 °C, the concentration of midgap electron traps in the active layers decreases from 4×1015 to less than 3×1013 cm−3 and the hole diffusion length in the layers improves from 2.0 to 2.6 μm. For cells grown at 750 °C, an efficiency of 14.6% (AM1.5, 100 mW/cm2 for an active area) is obtained.

Impact of the growth temperature on the performance of 1.70-eV Al0.22Ga0.78As solar cells grown by MBE

“…The lower EQE at longer wavelengths, with a characteristic shoulder in the EQE curve close to the band-edge, is a well-known phenomenon for AlxGa1-xAs solar cells [8][9][10][11][12]. It has been demonstrated that this issue can be addressed by using Se instead of Si as the dopant for the n-type regions [15].…”

“…Growth temperature has long been established as a key parameter in order to reduce oxygen contamination, and thus to enhance the material quality and performance of AlxGa1-xAs solar cells [6,[8][9]11], with the optimal temperature greatly dependent on the Al content x. In this contribution, we present and discuss recent progress in the MBE growth of 1.70-eV Al0.22Ga0.78As solar cells on GaAs substrates.…”

“…Extensive studies have been carried out in the past on high aluminum content (x≥20%) AlxGa1-xAs solar cells grown by MBE [6,[8][9][10][11] and MOCVD [12][13][14][15]. Most of these early devices exhibit poor performances, in particular a low open-circuit voltage (Voc) in regard of the bandgap of the active material.…”

Assessing material qualities and efficiency limits of III-V on silicon solar cells using external radiative efficiency

“…These are listed in Table I. We also calculated the EREs of III-V/Si and III-V solar cells in [15][16][17] using this approach. The results are listed in Table II.…”

Increased efficiency in multijunction solar cells through the incorporation of semimetallic ErAs nanoparticles into the tunnel junction

“…13 The poor performance of the conventional tunnel junction demonstrates the difficulty of making high quality tunnel junctions using conventional designs. The main limitation is the use of AlGaAs for the wider-band-gap cell; it is difficult to generate large photocurrent densities in an Al-GaAs cell due to defects which allow exciton recombination.…”