Weak localization and universal conductance fluctuations in multi-layer graphene

Hot Carriers in CVD-Grown Graphene Device with a Top h-BN Layer

“…The conductance fluctuations are observed, and they decrease as L increase from L = 0.32 to 50 K, which are typical properties in disordered mesoscopic graphene [24][25][26][27]. at various driving currents from I = 20 nA to 30000 nA at a fixed L of 0.32 K, which reveals similar conductance fluctuation characteristics by current heating in the nonequilibrium regime due to the hot carrier effects in disordered two-dimensional systems [18,[28][29][30][31].…”

“…Under the low-temperature limit ( L < BG ), BG ∼ 54 1/2 K ≅ 188.6 K with the carrier density = 12.2 in units of 10 12 cm −2 in sample B [13,32]. Consistently, e is proportional to ( 2 e − 2 L ) in sample B as shown in Figure 5(b), which belonged to Wiedemann-Franz law heat diffusion and corresponded to the transport situation for little carrier-phonon scattering for ≈ 1 [7,26]. Interestingly, the multilayer exfoliated graphene (sample B) has the same heat transfer mechanism ( ≈ 2) as the h-BN/graphene (sample A) systems [14][15][16].…”

“…Therefore, Figure 4(a) shows that e (I) of our sample A follows (1) with ≈ 0 and ≈ 1, which suggested little carrier-phonon scattering in two-dimensional material heterostructure systems [26]. Furthermore, one would be interested in whether the heat dissipation was transferred by another mechanism rather than carrier-phonon scattering.…”

“…In order to further discuss the linear relation between e and that indicates little carrier-phonon scattering in our sample A, we fabricate multilayer exfoliated graphene (sample B) that showed the same linear relation between e and by zero field resistance as a thermometer and conductance fluctuations due to its disordered property as in our previous reports [23][24][25][26]. Again, we are able to measure the conductance fluctuations for temperature and current dependence as shown in Figure 5(a) and inset [13].…”

Relationship between conductance fluctuation and weak localization in graphene

“…Taking into account that atomic scale defects cause the intervalley scattering, this further corroborates the obtained length scale matches between L i and L eff . A number of previous experimental data show fluctuations in ρ xx as a function of B 15,29,32,41,53 . We believe that we can extract L eff from these fluctuations by proper analysis.…”