Improved thermoelectric (TE) property involves low thermal conductivity (k) but high electrical conductivity (\(\sigma\)) and Seebeck coefficient (S). Experiment has confirmed that interfacial polarization electric (IPE) field (~ 1 MV/cm) of GaN/In_xGa_1−xN/GaN superlattices (SLs) enhances both S and \(\sigma\). In this work, role of IPE field on thermal boundary resistance (TBR) and in-plane (k_ip) as well as cross-plane thermal conductivities (k_cp) of indium-rich GaN/In_xGa_1−xN /GaN SLs (x ≥ 0.7) are explored theoretically. IPE field influences lattice vibrations on account of the inverse piezoelectric effect, resulting in modification of elastic and phonon properties of the SLs. Our results show that TBR is enhanced (2.10–5.30 × 10^–9 m² KW⁻¹) due to unequal changes in phonon velocity and specific heat on both sides of the interface leading to enhanced interface scattering, decreased phonon transmission, and more mismatches of acoustic properties. This caused reduction in k_ip and k_cp of the SL under the action of IPE field. Room temperature (RT) k_ip in the presence (absence) of IPE field of GaN (10 nm)/In_xGa_1−xN (5 nm) SL are 8.204(9.402) and 9.312(10.564) Wm⁻¹ K⁻¹ respectively, for x = 0.7 and 0.9, whereas RT k_cp for the same x are 4.871(6.012) and 6.083(7.327) Wm⁻¹ K⁻¹ exhibiting more than 20% reduction and are in good agreement with available experimental results of similar type of SLs. This work demonstrates that desired value of k can be achieved by tailoring polarization mechanism of nitride SLs for optimum TE power production at RT and above.

改进的热电 (TE) 属性涉及低导热率 ( k ) 但高导电率 ( \(\sigma\) ) 和塞贝克系数 ( S )。实验已经证实，GaN/In _x Ga _{1− x} N/GaN 超晶格 (SLs) 的界面极化电场 (IPE) 场 (~ 1 MV/cm ) 增强了S和\(\sigma\)。在这项工作中，IPE 场对富铟 GaN/In _x Ga _{1− x} N /GaN 的热边界电阻 (TBR) 和面内 ( k _ip ) 以及跨面热导率 ( k _cp ) 的作用SL ( x ≥ 0.7) 是理论上探讨的。由于逆压电效应，IPE 场会影响晶格振动，从而导致 SL 的弹性和声子特性发生改变。我们的结果表明，由于界面两侧声子速度和比热的不等变化导致界面散射增强、声子传输减少和更多失配，TBR 增强 (2.10–5.30 × 10 ^–9  m ²  KW ^-1 )的声学特性。这导致在IPE场作用下SL的k _ip和k _cp减少。存在（不存在）GaN (10 nm)/In _x的 IPE 场时的室温 (RT) k _ipGa _{1− x} N (5 nm) SL 分别为 8.204(9.402) 和 9.312(10.564) Wm ^-1  K ^-1，对于x  = 0.7 和 0.9，而对于相同的x，RT k _cp是 4.871(6.012) 和 6.083 (7.327) Wm ^-1  K ^-1表现出超过 20% 的减少，并且与类似类型 SL 的可用实验结果非常一致。这项工作表明，可以通过调整氮化物 SL 的极化机制来实现所需的k值，以在 RT 及以上条件下产生最佳的 TE 功率。