Syntheses of pure GeTe crystals from single source precursors (R2GeTe)3 (R=Et, Bu)

Anisotropic thermoelectric properties of GeTe single crystals

“…Methods for the preparation of GeTe single crystals with micrometre to millimetre size have been attempted, including solution-based chemical reactions, heterogeneous chemical reactions and Bridgeman method. [20][21][22][23][24] It should be noted that GeTe single crystals synthesized by heterogeneous chemical reactions are almost pure phase, excluding the inuence of Ge precipitation on the crystal structure and transport properties, 25 while it is inevitable for the melting method. The physical properties at room temperature of GeTe single crystals were studied by Koren et al 26 Neutron diffraction studies on the structural phase transition using GeTe single crystal samples were carried out by Chattopadhyay et al 10 The anisotropic magnetoresistance effect of GeTe single crystals was pointed out by Zhu et al 23 So far, no report on the anisotropy of thermoelectric properties at elevated temperatures for GeTe single crystals has been presented.…”

Low-Pressure CVD of GeE (E = Te, Se, S) Thin Films from Alkylgermanium Chalcogenolate Precursors and Effect of Deposition Temperature on the Thermoelectric Performance of GeTe

“…The benefits of using a single-source precursor include fine control over the stoichiometry, as this is designed into the precursor. These precursors include (R 2 GeTe) 3 , where R is Et or Bu, as described by Gupta et al for the thermal decomposition synthesis of GeTe nanoparticles; some often quite elaborate species, including [Ge­{N­(Me 2 SiCH 2 CH 2 Me 2 Si)} 2 i Pr­(Te i Pr)] used in the metal–organic CVD of GeTe thin films by Chen et al. ; [Ge­(Me 2 NCH 2 CMe 2 O) 2 S] and [Ge­(Me 2 NCH 2 CMe 2 S) 2 E] (where E is Se or Te) described for the thermal decomposition synthesis of GeE by Kim et al; [Ge­(S 2 COR′) 4 ] (R′ = Et or i Pr) and [ n Bu 2 Ge­(S 2 CO i Pr) 2 ] described by Shah et al for thermolysis to make GeS; and the use of [Ge­(Te n Bu) 4 ] in LPCVD of GeTe described in our previous work .…”

[Ge(TenBu)4] – a single source precursor for the chemical vapour deposition of germanium telluride thin films

“…A small number of single source precursors for the deposition of GeTe crystals are reported in the literature, although, with one exception (below), these have not been used for the CVD of GeTe thin films. Gupta et al synthesised (R 2 GeTe) 3 (R = Et, Bu) (1) from the reaction of Li 2 Te and R 2 GeCl 2 , and thermal decomposition of the precursor in trioctylphosphine at 300°C resulted in rhombohedral GeTe, 38 while Kim et al showed that thermal decomposition of [Te = Ge(dmampS) 2 ] (2) in hexadecane at 270°C produced Te-rich rhombohedral Ge 40 Te 57 . 39 There is just one previous example of a single source CVD precursor for the deposition of GeTe thin films.…”