Bilayer graphene is very attractive for both the fundamental and technological standpoint due to the possible modulation of its physical properties by opening a bandgap. In this work, we show that the thermoelectric properties of bilayer graphene single and double barrier structures can be modulated by the bandgap opening. The effect of the bandgap on the thermoelectric properties was investigated by describing the charge carriers in bilayer graphene as massive Dirac electrons in combination with the hybrid matrix method and the Landauer–Büttiker formalism. Thermoelectric properties such as the Seebeck coefficient, power factor, figure of merit, output power and efficiency are analyzed. In the case of single barriers, we find that at low temperatures the thermoelectric properties enhance at a critical bandgap, while at $T=200$ K they reduce systematically as the bandgap increases. In particular, the figure of merit increases up to 0.65 for a bandgap of 30 meV and decreases up to 0.8 for a bandgap of 40 meV, representing an enhancement and a reduction of about 30% and 56% with respect to the gapless case. In the case of double barriers, the thermoelectric properties have a contrasting dynamic with the bandgap opening with respect to single barriers. At $T=200$ K the thermoelectric properties enhance at a critical bandgap, and at low temperatures they collapse in effective terms with the bandgap opening. Here, the figure of merit increases up to 5.2 for a bandgap of 20 meV and decreases up to 1.3 for a bandgap of 40 meV, constituting an enhancement and reduction of 11% and 73%, respectively. We also find that the charge neutrality point and Breit–Wigner resonances shape the thermoelectric response at low temperatures, while at $T=200$ K the Fano resonances determine the thermoelectric properties. In addition, we corroborate that the redistribution–accumulation of electronic states caused by the bandgap opening is behind the enhancement–reduction of the thermoelectric properties. Our results indicate that bandgap opening could be a versatile mechanism to modulate the thermoelectric performance of bilayer graphene barrier structures.

由于可能通过打开带隙来调节其物理性质，双层石墨烯在基础和技术方面都非常有吸引力。在这项工作中，我们表明双层石墨烯单势垒和双势垒结构的热电特性可以通过带隙开口进行调制。通过将双层石墨烯中的电荷载流子描述为大质量狄拉克电子，并结合混合矩阵方法和 Landauer-Büttiker 形式，研究了带隙对热电特性的影响。分析了塞贝克系数、功率因数、品质因数、输出功率和效率等热电特性。在单势垒的情况下，我们发现在低温下，热电性能在临界带隙处增强，而在$吨=200$K 随着带隙的增加，它们会系统地减小。特别是，对于 30 meV 的带隙，品质因数增加至 0.65，而对于 40 meV 的带隙，品质因数减少至 0.8，相对于无间隙情况，品质因数提高和降低约 30% 和 56%。在双势垒的情况下，热电特性与带隙开口相对于单势垒具有对比动态。在$吨=200$K 热电特性在临界带隙处增强，并且在低温下它们随着带隙开口有效地坍缩。这里，对于 20 meV 的带隙，品质因数增加到 5.2，对于 40 meV 的带隙，品质因数减少到 1.3，分别构成 11% 和 73% 的增强和减少。我们还发现电荷中性点和 Breit-Wigner 共振塑造了低温下的热电响应，而在$吨=200$K Fano 共振决定了热电特性。此外，我们证实了由带隙开口引起的电子态的重新分布 - 积累是热电特性增强 - 降低的背后。我们的结果表明，带隙开口可能是一种调节双层石墨烯势垒结构热电性能的通用机制。