Van der Waals epitaxial MOCVD-growth of (Bi_xSb_1−x)₂Te₃(0 <x< 1) films

Abstract

Epitaxial (BixSb1-x)2Te3 with (0<x<1) were grown by MOCVD process at 400 °C using the tailormade precursors Et2Te2, i-Pr3Sb and Et3Bi. The films grown on Al2O3(0001) substrates show a very smooth surface morphology as was shown by SEM, AFM and TEM, while those grown on Si(100) are rather polycrystalline. The chemical composition of the crystalline films (XRD) was investigated by EDX and XPS and the in-plane transport properties were measured and a strong dependency from the bismuth content was found, which allows the tuning of the carrier concentration and mobility in a wide range.

Epitaxial and large area Sb2Te3thin films on silicon by MOCVD

“…So far, the most promising results in Sb 2 Te 3 growth were achieved employing trialkylstibines (such as SbMe 3 , Sb i Pr 3 ) and diallyltellanes (TeEt 2 , Te i Pr 2 ) as precursors; however, temperatures greater than or equal to 400 C were required, along with a dihydrogen partial pressure, to sustain the precursors' pyrolysis. 32,35 The more engineered species Et 2 Te 2 34,44 and (Et 2 Sb) 2 Te 33 have also been adopted for high-temperature depositions. Nevertheless, the high deposition rate required to achieve a uniform and well-oriented crystalline Sb 2 Te 3 MOCVD resulted in lms several hundreds of nanometers thick.…”

Structural and thermoelectrical characterization of epitaxial Sb2Te3 high quality thin films grown by thermal evaporation

“…An angle-dependent measurement was used to calculate the thickness of the oxidized surface layer. The XPS study shows a partially oxidized surface of 3.2±1.1 nm thickness [22].…”

“…The XPS study shows a partially oxidized surface of 3.2 ± 1.1 nm thickness. [22] Figure 9. XPS core level Sb (left) and Te (right) spectra of a Sb2Te3 film grown at 350 °C on a Al2O3(0001) substrate.…”

Influence of Nanoparticle Processing on the Thermoelectric Properties of (BixSb1−X)2Te3 Ternary Alloys

“…Such phenomena selectively reduce the lattice thermal conductivity in nanostructured materials such as nanoparticles and thin films due to the additional scattering of heat carrying phonons at grain boundaries and interfaces. [9,11,25,27,[29][30][31][32][33] As a result, the synthesis of chalcogenide-based nanostructures of various shape and size has been widely studied using a variety of methods such as electrochemical deposition, solvothermal or hydrothermal approaches [18,[34][35][36] as well as microwave-assisted approaches, [37] mechanical alloying, [38] and gas phase processes (i. e. atomic layer deposition ALD, [39,40] metal organic vapor deposition MOCVD, [41][42][43][44] physical vapor deposition PVD). [45,46] Nevertheless, (Bi x Sb 1À x ) 2 Te 3 ternary solid solutions have demonstrated higher zT values than their binary counterparts, mainly due to their larger unit cell size, lower crystal symmetry, and higher site-occupancy disorder.…”