Reciprocal space mapping of ordered domains in InxGa1−xP

Abstract

We applied high resolution x-ray diffraction techniques to determine the three dimensional domain shape in nominally lattice-matched, CuPt B ordered, In x Ga 1-x P epitaxial layers deposited on GaAs by metal organic vapor phase epitaxy. A technique of reciprocal space mapping is described which provides threedimensional information on the shape and size of the ordered domains. The domain shape is obtained by reciprocal space mapping along orthogonal crystallographic directions. Applying this technique shows that, at large miscut angles, the domains are oriented close to the growth direction, and are elongated by differing extents along the [110] and [ -110].

Analysis of polarized photoluminescence emission of ordered III–V semiconductor quaternary alloys

“…The polarization angular dependence of the PL emission of the epitaxial layer, propagating along one of three different crystallographic directions, [001] (from the surface), [1][2][3][4][5][6][7][8][9][10] and [110] (from the edge planes), were measured on three different epitaxial quaternary layers. The measured polarization patterns were compared with the normalized calculated curves.…”

“…If the same set of diagonal planes is involved, the polarization patterns of the PL emission from the two edge planes of the structure will be distinct, as it was observed on Sample 1. On the contrary, if the ordering in group III and V sublattices occurs in different sets of diagonal planes, such as the set of [ À 111] and [1][2][3][4][5][6][7][8][9][10][11] planes, the PL polarization pattern from the surface, due to the ordering within both sublattices, will be oriented on the same direction, and the PL polarization degree will increase proportionally to the polarizations caused by each one of the ordered sublattices. However, the orientation of the PL polarization patterns from the edge planes will not be along the same direction and the sum of these PL intensities will be similar to that observed on Sample 3.…”

“…For quaternaries this method cannot be applied, because the values of the bandgap of the fully ordered alloy for each one of the possible atomic compositions matched to the substrate is not known. Morever, atomic ordering is never uniform, but occurs only within some clusters with a characteristic size, which, depending on growth conditions, can vary from Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jlumin 100 nm to 1 μm in different structures [9,10]. Ordering in III-V alloys reduces the band-gap energy; as a result, the ordered alloy consists of ordered clusters within a disordered matrix with a higher band-gap value.…”

Influence of the degree of order of InGaP on its hardness determined using nanoindentation

“…6,14,15 In the case of CuPt B , the unit cell dimension is twice that of the bulk zincblende cell. 6,14,15 In the case of CuPt B , the unit cell dimension is twice that of the bulk zincblende cell.…”

“…By changing the ratio of In to Ga, the band gap energy of InGaP can be tuned. 6 Hardness refers to a material's resistance to permanent deformation or damage. InGaP undergoes spontaneous atomic ordering during growth.…”