Negative terahertz conductivity and amplification of surface plasmons in graphene–black phosphorus injection laser heterostructures

Abstract

We propose and evaluate the heterostructure based on the graphene-layer (GL) with the lateral electron injection from the side contacts and the hole vertical injection via the black phosphorus layer (PL) (p + PL-PL-GL heterostructure). Due to a relatively small energy of the holes injected from the PL into the GL (about 100 meV, smaller than the energy of optical phonons in the GL which is about 200 meV), the hole injection can effectively cool down the two-dimensional electronhole plasma in the GL. This simplifies the realization of the interband population inversion and the achievement of the negative dynamic conductivity in the terahertz (THz) frequency range enabling the amplification of the surface plasmon modes. The later can lead to the plasmon lasing. The conversion of the plasmons into the output radiation can be used for a new types of the THz sources.

Negative Terahertz Conductivity at Vertical Carrier Injection in a Black-Arsenic-Phosphorus–Graphene Heterostructure Integrated With a Light-Emitting Diode

“…These values of the absorption coefficient mentioned above, are markedly higher than the absorption coefficient, −α a−c ω , associated with the free carrier absorption in the absorbing-cooling layer near the GL where the plasmons are located. (in the direction perpendicular to the GL plane) [35]. At n GL ≃ n 0 ≃ (10 16 − 10 18 ), i.e., at the values corresponding to Fig.…”

“…This material can provide the enhanced dynamic properties of the carriers in the GL beneficial for achieving the negative THz conductivity. However, the interaction of the carriers with the interfacial optical phonons can lead to a complex pattern of the interband and intraband relaxation processes in the GLS [34,35].…”

Far-infrared photodetection in graphene nanoribbon heterostructures with black-phosphorus base layers

“…is the factor describing the contribution of the plasmonic resonances [compare Eqs. (17) and (22)] and…”

“…[9][10][11][12][13][14][15][16][17][18][19] The heterostructures, in which GLs or GNR arrays are integrated with the bP layers, can exhibit additional functionalities. [20][21][22][23][24][25][26] This is due to the special GL and GNR and the bP layers' band alignment (the Dirac point in the GLs and GNRs corresponds to the energy gap in the bP) and relatively narrow energy gap (Δ G ≃ 300 meV) in the bP layers with a sufficiently large number of atomic sheets. 27 The GL-and GNR-heterostructures with the black-arsenic (bAs) layers having even smaller band gaps [28][29][30][31][32] demonstrate similar properties.…”

Theoretical analysis of injection driven thermal light emitters based on graphene encapsulated by hexagonal boron nitride

“…Heterostructures with graphene layers (GLs) are promising building blocks for infrared and terahertz photodetectors [1-14], optical modulators [15][16][17][18], plasmonic and frequency multiplication devices [19][20][21][22][23][24][25][26][27][28], and lasers and light-emitting diodes [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44] (including those based on hybrid GL/black phosphorous devices [45,46]). The realization of the onchip monolithic nanoscale relatively simple light sources for high-bandwidth inter-and intra-chip connections is still a challenging problem [47].…”