Electrical and compositional properties on Bridgman-grown Gd-doped GaSb substrates

Abstract

In this work pure and Gd-doped GaSb ingots with different dopant concentrations were grown by the Bridgman Method. The compositional and electrical analysis carried out on these materials have shown the dependence of these results on the initial dopant concentration. The analysis have revealed the presence of inclusions which have been identified as Gd-Sb precipitates. The doped material was found to be p-type with a maximum value of the carrier density at the central region of the ingots. It has been also demonstrated that the Gd enhances the A band emission reducing the band-gap emission.

Cathodoluminescence from Er2O3-doped n-type GaSb:Te crystals

“…Doping with Er 2 O 3 causes increase of the total CL intensity as well as spectral changes. It has been previously reported [4] that Te codoping favours Er emission. Figure 1 shows the CL spectra of undoped GaSb, of Er 2 O 3 powder and of the Te-doped and Er 2 O 3 -codoped samples investigated in this work.…”

“…The CL images showed differences not only among different ingots but also from samples obtained from different positions along the growth axis of a given ingot. This is due to the inhomogeneous distribution of Te around defects and cracks in the samples as measured by x-ray microanalysis [4]. Figure 4(a) shows a CL image of ingot A, showing parallel bands with sets of aligned dots surrounded by intense haloes and figure 4(b) shows a more complex halo contrast.…”

“…Three Er-doped and Te-codoped polycrystalline GaSb ingots, 12 mm in diameter and 70 mm in length, were grown in a single-zone rotating Bridgman furnace. Details of the growth method are described in [4]. The ingots were grown with a constant Er concentration of 2 × 10 19 cm −3 and Te concentrations in the melt of 2 × 10 19 cm −3 (ingot A), 1 × 10 19 cm −3 (ingot B) and 4 × 10 19 cm −3 (ingot C) respectively.…”

Cathodoluminescence study of ytterbium doped GaSb

“…The influence of Nd [8] and Gd [6] doping on luminescence and defect structure of GaSb has been also reported.…”

“…GaSb, with a band gap of about 0.8 eV, and GaSb based structures are materials of increasing interest for a number of potential applications in the infrared range [1] as for instance thermo-photovoltaic cells, laser diodes or photodetectors with high quantum efficiency. Rare earth ions (Er, Nd and Gd) have been incorporated into GaSb by doping during the growth process and the structural and luminescence properties of the crystals have been investigated [2][3][4][5][6][7][8]. Er doping has been found [2,7] to produce a marked increase of the cathodoluminescence intensity of GaSb as well as a decrease of the emission bands related to native acceptors (band A) and to the presence of Te.…”