Origin of a localized vibrational mode in a GaSb substrate with a MBE-grown ZnTe epilayer

Abstract

A localized vibrational mode (LVM) with a remarkable fine structure is observed in the infrared transmission spectrum of a ZnTe epilayer grown with molecular beam epitaxy (MBE) on a GaSb substrate. On the basis of the Zn and Te deposited on the GaSb substrate during the MBE growth of ZnTe, and assuming diffusion of Zn and Te into GaSb, the LVM is attributed to Zn, substitutionally replacing either the cation, Ga (Zn Ga ), or the anion, Sb (Zn Sb ). The frequency of the LVM and its fine structure can then be interpreted in terms of the infrared active modes of 64 Zn substituting for Sb as an anti-site impurity and treating the centre as an XY 4 quasimolecule. With X≡ 64 Zn and Y≡ 69 Ga and 71 Ga, occupying the nearest-neighbour sites reflecting all the possible combinations and permutations as well as the natural isotopic abundance of Ga, the fine structure of the LVM can be accounted for quantitatively.

Host isotope effects on the oxygen local vibrations in CdTe

“…Observed transitions are attributed to the normal modes of OCd 4 quasimolecule corresponding to G 5 modes of T d symmetry. Despite the simplicity of this model it does give quite accurate results as confirmed by this work as well as the earlier works of Sciacca [16], Theis [15], Kim [22], etc. Even though the entire line shape of the 350 cm −1 LVM band is reproduced very well by this model, lack of fine structure in the absorption band is attributed to the small atomic mass of an oxygen impurity compared to that of the NN Cd atoms.…”

Optical investigation of GaSb thin films grown on GaAs by metalorganic magnetron sputtering

“…The III-V compound semiconductor gallium antimonide (GaSb) has in recent years attracted much attention as an important material for infrared (IR) optoelectronic and electronic device in the wavelength range 1-5 μm [1][2][3][4][5][6][7][8][9][10][11][12][13]. GaSb has an energy bandgap of 0.70 eV (1.77 μm) at room temperature (RT) and 0.81 eV (1.53 μm) at 4 K [14].…”