TY - JOUR
T1 - Critical thickness for giant thermoelectric Seebeck coefficient of 2DEG confined in SrTiO3/SrTi0.8Nb0.2O3 superlattices
AU - Ohta, Hiromichi
AU - Mune, Yoriko
AU - Koumoto, Kunihito
AU - Mizoguchi, Teruyasu
AU - Ikuhara, Yuichi
N1 - Funding Information:
This work was financially supported by the Industrial Technology Research Grant Program in 2005 from the New Energy and Industrial Technology Development Organization (NEDO), and Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology (no. 18686054).
PY - 2008/7/1
Y1 - 2008/7/1
N2 - Seebeck coefficient (|S|) of two-dimensional electron gas (2DEG) confined within (SrTiO3)LB/(SrTi0.8Nb0.2O3)LW superlattices were measured at room temperature to clarify the critical thicknesses of barrier SrTiO3 (LB) and well SrTi0.8Nb0.2O3 (LW) for giant |S| [H. Ohta et al., Nat. Mater. 6, 129 (2007)]. The |S| values of the superlattices increased proportionally to LW- 1/2 due to increasing of the density of states near the conduction band edge (quantum size effect), and reached 300 μV K- 1 at LW = 1 unit cell SrTi0.8Nb0.2O3 (0.39 nm), which is ∼ 5 times larger than that of the SrTi0.8Nb0.2O3 bulk (60 μV K- 1). The critical thickness of LB and LW for giant |S| was clarified to be 16 unit cells (6.25 nm). The best thermoelectric performance can be obtained at (LB, LW) = (16, 1).
AB - Seebeck coefficient (|S|) of two-dimensional electron gas (2DEG) confined within (SrTiO3)LB/(SrTi0.8Nb0.2O3)LW superlattices were measured at room temperature to clarify the critical thicknesses of barrier SrTiO3 (LB) and well SrTi0.8Nb0.2O3 (LW) for giant |S| [H. Ohta et al., Nat. Mater. 6, 129 (2007)]. The |S| values of the superlattices increased proportionally to LW- 1/2 due to increasing of the density of states near the conduction band edge (quantum size effect), and reached 300 μV K- 1 at LW = 1 unit cell SrTi0.8Nb0.2O3 (0.39 nm), which is ∼ 5 times larger than that of the SrTi0.8Nb0.2O3 bulk (60 μV K- 1). The critical thickness of LB and LW for giant |S| was clarified to be 16 unit cells (6.25 nm). The best thermoelectric performance can be obtained at (LB, LW) = (16, 1).
KW - Seebeck coefficient
KW - SrTiO
KW - Superlattices
KW - Thermoelectric energy conversion
KW - Two-dimensional electron gas (2DEG)
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U2 - 10.1016/j.tsf.2007.10.034
DO - 10.1016/j.tsf.2007.10.034
M3 - Article
AN - SCOPUS:44249113837
VL - 516
SP - 5916
EP - 5920
JO - Thin Solid Films
JF - Thin Solid Films
SN - 0040-6090
IS - 17
ER -