Extreme selectivity in the lift-off of epitaxial GaAs films

Abstract

Generally and in one form of the invention this is a periodic surface filter comprising at least one element at a surface of the filter and electronic controls to change the optical characteristics of the element. Other methods and devices are disclosed.

Above band gap absorption spectra of the arsenic antisite defect in low temperature grown GaAs and AlGaAs

“…13 The ELO was done by using 10% HF, which etches the AlAs sacrificial layer highly selective against GaAs. To obtain a thin LTAlGaAs layer, we polished the substrate of the pieces of sample C down to roughly 100 m and used a selective etchant based on citric acid and hydrogen peroxide 14 to remove the remaining substrate.…”

Polarization dependence of the electroabsorption in low-temperature grown GaAs for above band-gap energies

“…The interdigitated finger contacts had a width of 1 m and a spacing varying between 1 and 14 m. The total device area was 100 mϫ100 m. To perform transmission measurements at photon energies far above the band gap, the LT-GaAs layer was separated from the substrate using an epitaxial liftoff technique. 10 Before and after the epitaxial liftoff the I -V characteristics of the devices were nearly identical, indicating that the liftoff process does not influence the electrical properties of the LT layer. Due to the high resistance of annealed LTGaAs we obtained very low dark currents, e.g., 2 A at 40 V for 3 m finger spacing.…”

Photonic crystals in the optical regime — past, present and future

“…The development of ELO was originally motivated by the need for cheaper substrates in the solar cell industry, since the original substrates can be re-used after the epilayer has been lifted o! [55,56]. The technique is also very promising for GaAs-on silicon optoelectronics [57] and the fabrication of e$cient light-emitting diodes [58].…”