Pulsed Electroplating: a Derivate Form of Electrodeposition for Improvement of (Bi1−x Sb x )2Te3 Thin Films

Abstract

Bismuth antimony telluride (Bi 1Àx Sb x ) 2 Te 3 thermoelectric compounds were synthesized by pulse plating. Due to the large number of parameters available (pulse waveform, on/off pulse time, applied current density), this advanced form of electrodeposition allows better control of the interfacial supply and electrochemical reactions and offers effective ways to improve macroscopic properties such as adhesion and to produce crack-free hard deposits and finegrained films with higher uniformity and lower porosity. The influence of pulse parameters (pulse time t on , cathodic current density J c ) on the stoichiometry, roughness, and crystallography of deposits was studied. The thermoelectric properties (electrical resistivity and Seebeck coefficient) of the films were measured. The results revealed that deposits have p-type conductivity directly after electroplating (Seebeck coefficient around 150 lV K À1 ), in contrast to films synthesized by direct current, which require annealing. An improvement of resistivity was observed: for a direct-current-deposited film the resistivity is around 5000 lX m, whereas for a pulse-deposited film the resistivity was around 200 lX m.

Towards thermoelectric nanostructured energy harvester for wearable applications

“…The maximum values of Seebeck coefficients were -52 µV/K and 120 µV/K for raw Bi 2 Te 3 and Bi 0.5 Sb 1.5 Te 3 electroplated films, respectively. Deviation from stoichiometric composition can be one of the reasons that Bi 0.5 Sb 1.5 Te 3 Seebeck coefficients were below the maximum values previously achieved by electrodeposition [57]. In addition, the physical properties performance of electroplated films Bi 2 Te 3 and Bi 0.5 Sb 1.5 Te 3 needs to be improved further.…”

Pulsed electrodeposition and characterization of Bi2Te3−ySey films

“…And the peak intensities agree with the reported data of Bi 2 Te 2.5 Se 0.5 without preferential orientations, which is in agreement with the result reported in Refs. [17,20]. Whereas the films deposited by continuous electrodeposition usually showed a preferential orientation along (1 1 0) [15,21].…”

“…Bi 2 Te 3Ày Se y and Bi 2Àx Sb x Te 3 as the most efficient n-and p-type TE materials, respectively, around room temperature, have attracted great attention recently [15][16][17]. Richoux et al [17] prepared a Bi 0.38 Sb 1.43 Te 3.19 film by a pulsed electrodeposition method and measured the TE properties after transferring the film onto a non-conducting epoxy support.…”

“…Richoux et al [17] prepared a Bi 0.38 Sb 1.43 Te 3.19 film by a pulsed electrodeposition method and measured the TE properties after transferring the film onto a non-conducting epoxy support. The Seebeck coefficient and electrical resistivity of the film were 230 mV/K and 184 mV m, respectively.…”

Влияние термообработки на структуру и термоэлектрические свойства тонких пленок Sb-=SUB=-0.9-=/SUB=-Bi-=SUB=-1.1-=/SUB=-Te-=SUB=-2.9-=/SUB=-Se-=SUB=-0.1-=/SUB=- и композитов на их основе

“…Согласно [18], размеры атомов, входящих в твердый раствор Bi 0.9 Sb 1.1 Te 2.9 Se 0.1 , имеют следующие значения: для Bi 0.17 nm, для Sb 0.159 nm, для Te 0.16 nm и для Se 0.14 nm. Поскольку атомные радиусы Sb и Te при-близительно равны, а Se в полученных тонких пленках значительно меньше, чем Te, меньшие по сравнению со справочными данными значения параметров a и c могут являться следствием наличия в кристаллической решетке дефектов вакансионного типа.…”