Topological insulator thin films starting from the amorphous phase-Bi2Se3 as example

Abstract

We present a new method to obtain topological insulator Bi2Se3 thin films with a centimeter large lateral length. To produce amorphous Bi2Se3 thin films we have used a sequential flash-evaporation method at room temperature. Transmission electron microscopy has been used to verify that the prepared samples are in a pure amorphous state. During annealing the samples transform into the rhombohedral Bi2Se3 crystalline strcuture which was confirmed using X-ray diffraction and Raman spectroscopy. Resistance measurements of the amorphous films show the expected Mott variable range hopping conduction process with a high specific resistance compared to the one obtained in the crystalline phase (metallic behavior). We have measured the magnetoresistance (MR) and the Hall effect (HE) at different temperatures between 2 K and 275 K. At temperatures T 50 K and fields B 1 T we observe weak anti-localization in the MR; the Hall measurements confirm the n-type character of the samples. All experimental results of our films are in quantitative agreement with results from samples prepared using more sophisticated methods.

Low-temperature Hall effect in bismuth chalcogenides thin films

“…4(a) and 4(d)], and in Ref. [33] ( Fig. 8), one can see correlation between the low-T resistivity upturn and increase of the Hall coefficient; remarkably, the resistivity per square for these films and the scale of the Hall coefficient variation are comparable to those for our samples.…”

Evidence of robust 2D transport and Efros-Shklovskii variable range hopping in disordered topological insulator (Bi2Se3) nanowires

“…39,40 In a previous work on Bi 2 Se 3 thin films, the characteristic temperature 𝑇 𝑜 in Eq. ( 9) was found to be ~ 10 6 K. 64 But in our case, it is 940.7 K and 23.42 K for W3 and W6, respectively. Since, the hopping potential is proportional to 𝑇 𝑜 , we can conclude that the energy required by electron to hop from one localized state to another is very small in our case.…”

The dimensional crossover of quantum transport properties in few-layered Bi2Se3 thin films

“…[33][34][35] To obtain a greater transport contribution from the topological SS, it is important to obtain TI thin lms with a high crystallization quality. The methods usually used for preparing TI thin lms include molecular beam epitaxy (MBE), 33,[36][37][38][39][40] chemical vapor deposition, [41][42][43][44] physical vapor deposition, [45][46][47][48] pulsed laser deposition (PLD) [49][50][51][52][53][54][55][56][57][58][59][60] and sputtering. 61,62 The MBE is the method mainly used to obtain at and thin TI lms for fundamental research, because of its advantages of 2D growth, single crystal yield and easily controlled doping.…”