2018年6月25日星期一

Formation of porous layers on n-GaSb by electrochemical etching

The effect of electrochemical etching of n-type GaSb in aqueous solutions of HCl and HF has been analysed. By anodization in HCl, two different morphologies of porous layers were observed depending on the current density. At low current density (0.5 mA cm−2) a macroporous layer is formed with the pores following preferential directions, while at high current density (15 mA cm−2) pores of sizes less than 100 nm were observed. Furthermore, a comparison between the luminescence in the porous layer and bulk GaSb is also performed. On the other hand, anodization in HF leads to an electropolishing process and no porosification is obtained.

Source:IOPscience

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2018年6月5日星期二

Absorption and dispersion in undoped epitaxial GaSb layer

In this paper, we present the results of a theoretical and experimental investigation into the refractive index and absorption, at room temperature, of a 4 μm-thick undoped epitaxial layer of GaSb deposited on a GaAs substrate. A theoretical formula for optical transmission through an etalon was derived, taking into account the finite coherence length of the light. This formula was used to analyse the measured transmission spectra. The refractive index was determined in a wide spectral range, between 0.105 eV and 0.715 eV. The absorption was determined for photon energies between 0.28 eV and 0.95 eV. An Urbach tail was observed in the absorption spectrum, as well as a constant increase in absorption in the spectral region above the band gap.


Source:IOPscience

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