Electric Transport and Infrared Property of (Bi0.85Sb0.15)1-xAsx

doi:10.15541/jim20170486

Abstract

Abstract:

(Bi₈₅Sb₁₅)_100-_xAs_x alloys were grown by melting stoichiometric mixture of elements Bi, Sb, and As. The phases and components of samples were analyzed by X-ray diffraction and the energy dispersion analysis. The As-doped (less than 8% in nominal) alloys have no impurity phases. Below T =100 K, Bi_0.85Sb_0.15 reveals semiconductor behavior in temperature dependent dc-resistivity, whereas (Bi_0.85Sb_0.15)_0.95As_0.05shows a metallic characteristic in the measured temperature range. The plasma of Bi_0.85Sb_0.15 shift towards low energy in far infrared reflectance spectra with the decrease of temperature, indicating thermally excited response of free electrons. Comparing with undoped Bi_0.85Sb_0.15, the plasma frequency of 5% As doped compound changes slightly, whereas the scattering rate of the free carriers increases. The infrared conductivity spectrum is enhanced in the range 600 cm^-1-2000 cm^-1, due to the formation of tails of the energy bands. Combining with the dc electric transport and the analysis of infrared properties, the Fermi level of (Bi_0.85Sb_0.15)_0.95As_0.05 possibly is not situated in the localized states, but in delocalized range.

Key words: infrared spectra, Bi-Sb alloys, As doping

CLC Number:

O469
O43

CAI Li-Jun, SHI Xuan-Dai, WU Ji-Qiong, ZHU Sheng-Yun, HUANG Yao, HOU Yan-Hui, MA Yong-Chang. Electric Transport and Infrared Property of (Bi_0.85Sb_0.15)_1-_xAs_x[J]. Journal of Inorganic Materials, 2018, 33(7): 761-766.

Figures/Tables 7

Fig. 1 XRD patterns of (Bi0.85Sb0.15)1.0-xAsx alloys

Table 1 Content of As in samples and lattice sizes

Nominal content As/%	Measured content As/%	Crystal lattice a/nm	Crystal lattice c/nm
0	0	0.4552	1.1913
5	2.5	0.4528	1.1842
8	3.8	0.4487	1.1811

Fig. 2 Elements mapping of Sb(a), Bi(b) and As(c) in a range of 20 μm×20 μm in (Bi0.85Sb0.15)0.95As0.05, microphologies of the cleaved surface of undoped Bi0.85Sb0.15 (d) and (Bi0.85Sb0.15)0.95As0.05 sample (e) The rectangles present the scanning area for (Bi0.85Sb0.15)0.95As0.05 and undoped Bi0.85Sb0.15, respectively

Fig. 3 Temperature dependent resistivity of (Bi0.85Sb0.15)1.0-xAsx (x=0, 5%, 8%) Inset shows the temperature dependence of Hall coefficient

Fig. 4 Infrared reflectivity of Bi0.85Sb0.15 at various temperatures The arrows represent positions of the plasma edges

Fig. 5 Infrared reflectivity of the undoped Bi0.85Sb0.15 and (Bi0.85Sb0.15)0.95As0.05 at 300 K

Fig. 6 Infrared conductivity spectra of the undoped Bi0.85Sb0.15 and (Bi0.85Sb0.15)0.95As0.05 at 300 KInset is the proposed diagram of energy bands structure (density of states, DOS) under ground state near the Fermi level

References 25

[1]	SNYDER G J, TOBERER E S.Complex thermoelectric materials.Nature Materials, 2008, 7(2): 105-114.
[2]	BENIA H, STRABER C, KERN K, et al. Surface band structure of Bi1-xSbx Surface band structure of Bi1-xSbx(111). Phys. Rev.B, 2015, 91(16): 161406(R)-1-5.
[3]	NOGUCHI H, KITAGAWA H, KIYABU T,et al. Low temperature thermoelectric properties of Pb- or Sn-doped Bi-Sb alloys. J. Phys. Chem. Solids, 2007, 68(1): 91-95.
[4]	LIU H J, SONG C M, WU S T,et al. Processing method dependency of thermoelectric properties of Bi85Sb15 alloys in low temperature. Cryogenics, 2007, 47(1): 56-60.
[5]	SUNGLAE C, YUNKI K, SUK Y, et al. Artificially ordered Bi/Sb superlatitice alloys: fabrication and transport properties. Phys. Rev. B, 2001, 64(23): 235330-1-4.
[6]	LENOIR B, CASSART M, MICHENAUD J P, et al. Transport properties of Bi-rich Bi-Sb alloys. J. Phys. Chem. Solids, 1996, 57(1): 89-99.
[7]	CHEN Z, ZHOU M, HUANG R J,et al. Thermoelectric properties of p-type Pb-doped Bi85Sb15-xPbx alloys at cryogenic temperatures. J. Alloys Compd., 2012, 511(1): 85-89.
[8]	ROGACHEVA E I, DROZDOVA A A, NASHCHEKINA O N, et al. Transition into a gapless state and concentration anomalies in the properties of Bi100-xSbx solid solutions. Appl. Phys. Lett., 2009, 94(20): 202111-1-4.
[9]	DUTTA S, SHUBHA V, RAMESH T G.Effect of pressure and temperature on thermopower of Bi-Sb alloys.Physica B, 2010, 405(5): 1239-1243.
[10]	SINGH S, GARCIA-CASTRO A C, IRAIS V, et al. Prediction and control of spin polarization in a Weyl semimetallic phase of BiSb. Phys. Rev. B, 2016, 94(16): 161116(R)-1-5.
[11]	ŞAHIN CÜNEYT, MICHAEL E FLATTÉ. Tunable giant spin hall conductivities in a strong spin-orbit semimetal: Bi1-xSbx. Phys. Rev. Lett., 2015, 114(10): 107201-1-5.
[12]	ZHANG H J, LIU C X, QI X L, et al. Electronic structures and surface states of the topological insulator Bi1-xSbx. Phys. Rev. B, 2009, 80(8): 085307-1-8.
[13]	BANERJEE A, FAUQUE B, IZAWA K,et al. Transport anomalies across the quantum limit in semi-metallic Bi0.96Sb0.04. Phys. Rev. B, 2008, 78(16): 161103-1-4.
[14]	HYUNGYU J, CHRISTOPHER M J, HEREMANS J P. Enhancement in the figure of merit of p-type Bi100-xSbx alloys through multiple valence-band doping. Appl. Phys. Lett., 2012, 101(5): 053904-1-5.
[15]	LUO T T, WANG S Y, LI H,et al. Low temperature thermoelectric properties of melt spun Bi85Sb15 alloys. Intermetallics, 2013, 32: 96-102.
[16]	TSUCHIYA Y.The molar volume of molten As-Sb, As-Bi and As-Te systems: further evidence for rapid structural changes in liquid As in the supercooled state.J. Non-Crystalline Sol., 1999, 250(2): 473-477.
[17]	阎守胜. 固体物理基础.北京: 北京大学出版社, 2000: 283-290.
[18]	DRESSEL M, GRUNER G.Electrodynamics of Solids: Optical Properties of Electrons in Matter. Beijing: Beijing World Publishing Corporation, 2005: 339-360.
[19]	DEAN N, PETERSEN C, FAUSTI D, et al. Polaronic conductivity in the photoinduced phase of 1T-TaS2.Phys. Rev. Lett., 2011, 106(1): 016401-1-4.
[20]	CHEN Z G, YUAN R H, DONG T, et al. Infrared spectrum and its implications for the electronic structure of the semiconducting iron selenide K0.83Fe1.53Se2. Phys. Rev. B, 2011, 83(22): 220507(R)-1-4.
[21]	BASOV D N, TIMUSK T.Electrodynamics of high-Tc superconductors. Rev. Mod. Phys., 2005, 77(2): 721-778.
[22]	HU B F, CHENG B, YUAN R H,et al. Coexistence and competition of multiple charge-density-wave orders in rare-earth tritellurides. Phys. Rev. B, 2014, 90(8): 085105-1-7.
[23]	陆栋, 蒋平. 固体物理学.北京: 高等教育出版社, 2011: 104-114.
[24]	RAVINDRA N M, SRIVASTAVA V K.Temperature dependence of the energy gap in Bi-Sb systems.J. Phys. Chem. Solids, 1980, 41(11): 1289-1290.
[25]	VURGAFTMAN I, MEYER J R, RAM-MOHAN L R. Band parameters for III-V compound semiconductors and their alloys.J. Appl. Phys., 2001, 89(11): 5815-5875.