Bulk transport properties of bismuth selenide thin films grown by magnetron sputtering approaching the two-dimensional limit

Abstract

We have investigated the transport properties of topological insulator Bi2Se3 thin films grown using magnetron sputtering with an emphasis on understanding the behavior as a function of thickness. We show that thickness has a strong influence on all aspects of transport as the two-dimensional limit is approached. Bulk resistivity and Hall mobility show disproportionately large changes below 6 quintuple layer which we directly correlate to an increase in the bulk band gap of few-layer Bi2Se3, an effect that is concomitant with surface gap opening. A tendency to crossover from a metallic to an insulating behavior in temperature-dependent resistivity measurements in ultra-thin Bi2Se3 is also consistent with an increase in the bulk band gap along with enhanced disorder at the film-substrate interface. Our work highlights that the properties of few-layer Bi2Se3 are tunable that may be attractive for a variety of device applications in areas such as optoelectronics, nanoelectronics and spintronics.

Signature of weak-antilocalization in sputtered topological insulator Bi2Se3 thin films with varying thickness

“…The increasing value of α with increasing film thickness describes that the contribution of surface states to the conduction is weak for thicker film 8 . The S1 and S2 samples magnetoconductivity curves have a clear WAL cusp which confirms the less elastic scattering and spin orbit scattering in low magnetic field region at 2 K 23 .…”

“…On the other hand, magnetron sputtering affords precise thickness control with uniform and high deposition rate for the preparation of large area thin films. As per existing literature, limited reports are available on Bi 2 Se 3 thin films grown by magnetron sputtering for study of WAL behavior in sputtered film 14 , 22 , 23 . The contributions of surface states and bulk carriers to total transport are highly dependent on the thickness of the film 16 .…”

Surface Defines the Properties: Colloidal Bi2Se3 Nanosheets with High Electrical Conductivity

“…DFT simulations of a thin slab of Bi 2 Se 3 reveal the appearance of a Dirac cone at the Γ point . Further decrease of the thickness from approximately 5 to 1 nm causes the interaction between the states on opposite surfaces, leading to the reopening of the band gap. , Our NSs comprise nearly 10 quintuple layers and thus offer a highly suitable solution-processable platform for the study of charge carriers in topologically nontrivial surface states.…”

Synthesis and characterization of bismuth selenide thin films by thermal evaporation technique

“…Thin films of Bismuth Selnide have wide technological applications in solar devices, optoelectronic chemical devices [12], optical recording system and decorating coatings [13]. There are various methods to synthesize thin films including: chemical deposition [14], Magnetron sputtering [15], Successive ionic layer adsorption (SILAR) method [16], Molecular beam epitaxy [17,18], Thermal evaporation [19] etc. In this communication, we report the synthesis of bulk bismuth selenide of different stoichiometries (0.123 to 0.309) by solid state reaction of bismuth and selenium.…”