Epitaxial Zinc-Blende CdTe Antidots in Rock-Salt PbTe Semiconductor Thermoelectric Matrix

Abstract

The formation of zinc-blende CdTe antidots (bandgap of 1.5 eV at room temperature) embedded in a rock-salt PbTe semiconductor matrix with a narrow bandgap of 0.3 eV in properly annealed epitaxial CdTe/PbTe multilayers grown by molecular beam epitaxy on a GaAs(001) substrate is reported. Transmission microscopy and X-ray diffraction characterization revealed the monocrystalline zinc-blende crystal structure of the CdTe antidots. The CdTe antidots have a highly symmetric shape and size varying in a controlled way in the range from 5 to 30 nm, depending on the layer thicknesses in the initial multilayer CdTe/PbTe stack. The presented results indicate that the CdTe antidot growth mechanism is similar to that of PbTe dots embedded in a CdTe matrix and is driven by the nanoscale phase separation due to qualitative differences in the chemical bonding and crystal structure of PbTe and CdTe. The electrical characterization in terms of Hall effect, electrical conductivity, and Seebeck effect measurements showed that both n- and p-type conductivities can be obtained in these nanocomposite thermoelectric materials with carrier concentrations of 1017–1018 cm–3 and mobilities of about 200 cm2/(V s) at room temperature. About a 25% increase of the thermoelectric power as compared to that of the reference bulk thermoelectric PbTe crystals was found in heterostructures with the smallest CdTe antidots.

Structural and electronic properties of Pb1−xCdxTe and Pb1Bukała1, Sankowski2, Buczko3 et al. 2012Phys. Rev. B24560View full textAdd to dashboardCite

“…It has been also shown that CdTe nano-clusters embedded in PbTe lead to considerable changes of the derivative of the carrier density of states at the Fermi level and can influence the thermoelectrical properties of the material. 13 These theoretical results together with the recently reported fabrication of CdTe quantum dots in a PbTe matrix 14 open doors for using PbTe-CdTe structures to enhance the performance of thermoelectric devices.…”

Unit cell distortion and surface morphology diversification in a SnTe/CdTe(001) topological crystalline insulator heterostructure: influence of defect azimuthal distribution

“…The same kind of CdTe buffer was earlier used by us for the growth of closely related PbTe/CdTe heterostructures. 58 The lattice parameter of rock-salt PbTe is equal to 6.46 Å, i.e. it is almost lattice matched to CdTe (6.48 Å).…”

Metal–organic coordinated multilayer film formation: Quantitative analysis of composition and structure

“…These systems have been integrated in a wide range of applications such as anti-fouling coatings or for drug delivery [8][9][10]. Inorganic examples of alternating layers for device architectures (i.e., capacitors and multilevel flash memory) are formed by traditional processing methods such as metal evaporation, ion beam sputtering, and molecular beam epitaxy as well as by nontraditional solution-phase layer-by-layer methods [11][12][13][14]. Metalorganic coordinated multilayers are a hybrid inorganic-organic system characterized by the ability to tailor and tune thickness in the subnanometer scale with chemically selective deposition [15][16][17][18][19][20][21][22][23][24][25][26].…”