Large-area 2D bismuth antimonide with enhanced thermoelectric properties via multiscale electron–phonon decoupling

Abstract

It is a challenge to obtain high thermoelectric efficiency, owing to the conflicting parameters of the materials that are required. In this work, the composition-adjustable 2D bismuth antimonide (Bi100-xSbx) is...

Lattice Dynamics, Transport and Thermoelectric Properties of Bi-Sb Alloys Obtained by Mechanical Alloying and Spark Plasma Sintering

“…This is in agreement with Olijnyk et al [56] and Höhne et al [61], who worked on bulk Bi and found a rather similar FWHM, but in contrast with the results of Lu et al who worked on thin film of Bi [62]. We found that the FWHM of the E g mode did not change significantly with Sb alloying, as also found by Zhao et al in the case of 2D layers of Bi 1−x Sb x for x ≤ 0.15 [58]. This was also the case for bulk Bi 0.9 Sb 0.1 compared to the Bi reference in Lannin's work [55] if we examine their Raman spectra in detail.…”

“…In the more recent works, Sultana et al also observed only additional peaks at about 120 cm −1 and 140 cm −1 [55], whereas Zhao et al observed only these peaks for x ≤ 0.18 and all the five peaks only for x ≥ 0.27 [56], and Lee et al observed only one weak additional peak at about 118 cm −1 in their sample with x =0.04 [60]. In contrast, in our samples, we observed the peak at around 110 cm −1 even for low Sb content, and it is located at lower frequencies than in single-crystalline samples [54,55] and the same frequency as in the 2D layer of Bi 0.65 Sb 0.35 studied by Zhao et al [58]. These differences are probably due to the small grain size and/or disordering in our samples.…”

“…Both studies also reported no clear trend for the frequency of A 1g at low Sb content, but a very small decrease with increasing Sb content at larger Sb content [54,55]. In more recent works, Sultana et al, in the case of single crystals [57], and Zhao et al, in the case of very thin 2D layers [58], also found an increase in the frequency of the E g mode with Sb content having a similar magnitude as in our work. However, Sultana et al found an increase in the frequency of the A 1g with Sb content [56], in contrast with our work and the early studies [54,55].…”

“…by Zhao et al in the case of 2D layers of Bi1−xSbx for x ≤ 0.15 [58]. This was also the case for bulk Bi0.9Sb0.1 compared to the Bi reference in Lannin s work [55] if we examine their Raman spectra in detail.…”