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Antimonide compounds are fabricated in membrane form to enable materials combinations that cannot be obtained by direct growth and to support strain fields that are not possible in the bulk. InAs/(InAs,Ga)Sb type II superlattices (T2SLs) with different in-plane geometries are transferred from a GaSb substrate to a variety of hosts, including Si, polydimethylsiloxane, and metalcoated substrates. Electron microscopy shows structural integrity of transferred membranes with thickness of 100 nm to 2.5 µm and lateral sizes from 24 × 24 µm 2 to 1 × 1 cm 2 . Electron microscopy reveals the excellent quality of the membrane interface with the new host. The crystalline structure of the T2SL is not altered by the fabrication process, and a minimal elastic relaxation occurs during the release step, as demonstrated by X-ray diffraction and mechanical modeling. A method to locally strain-engineer antimonide-based membranes is theoretically illustrated. Continuum elasticity theory shows that up to ∼3.5% compressive strain can be induced in an InSb quantum well through external bending. Photoluminescence spectroscopy and characterization of an IR photodetector based on InAs/GaSb bonded to Si demonstrate the functionality of transferred membranes in the IR range.antimonide | membranes | transfer | infrared | integration E pitaxially grown Sb compounds have recently received increasing attention as functional layers in IR detectors (1-4) and sources (5-9), high-mobility transistors (10-12), resonant tunneling diodes (13-15), and low-power analog and digital electronics (10,16). In this scenario we establish a versatile process to release and transfer Sb-based heterostructures from their epitaxial growth substrate to any host, resulting in fabrication of freestanding membranes (17,18). Despite the numerous demonstrations of membrane technology applied to III-V semiconductors (18-26), fabrication and detailed characterization of Sb compounds in membrane form has not been reported. For the purpose of this work we investigate InAs/(Ga,InAs)Sb type II superlattices (T2SLs) and AlInSb/InSb quantum wells (QWs), but our approach is readily applicable to any Sb-containing heterostructure. We demonstrate that wet and dry techniques (17, 18) (i.e., transfer in liquid or mediated by a stamp, respectively) yield successful transfer of T2SL membranes with thickness ranging from 100 nm to 2.5 µm, and lateral sizes going from 24 × 24 µm 2 to 1 × 1 cm 2 . We bond InAs/(InAs,Ga)Sb T2SLs to a large variety of hosts, including elastomers and rigid substrates, and both insulating and semiconducting substrates. Electron microscopy and X-ray diffraction (XRD) show that the crystal structure and the strain state of the materials are minimally altered during the release and transfer process. Mechanical modeling establishes that elastic strain up to ∼3.5% can be imparted in nanoscale-thickness AlInSb/InSb/AlInSb membranes by external bending. Finally, we demonstrate the functionality of Sbbased superlattices bonded to Si via photoluminescence (PL) and cha...

We have calculated and investigated the electronic states, dynamical polarization function and the plasmon excitations for $$\alpha -{\mathcal {T}}_3$$ α - T 3 nanoribbons with armchair-edge termination. The obtained plasmon dispersions are found to depend significantly on the number of atomic rows across the ribbon and the energy gap which is also determined by the nanoribbon geometry. The bandgap appears to have the strongest effect on both the plasmon dispersions and their Landau damping. We have determined the conditions when relative hopping parameter $$\alpha $$ α of an $$\alpha -{\mathcal {T}}_3$$ α - T 3 lattice has a strong effect on the plasmons which makes our material distinguished from graphene nanoribbons. Our results for the electronic and collective properties of $$\alpha -{\mathcal {T}}_3$$ α - T 3 nanoribbons are expected to find numerous applications in the development of the next-generation electronic, nano-optical and plasmonic devices.

We demonstrate that wrinkled graphene on Ge with nanoscale period and amplitude holds the potential to generate cyclotron-like radiation in the THz range of the electromagnetic spectrum. We show nanoscale graphene wigglers fabricated by release and transfer of atomically thin sheets to one-dimensional Ge gratings. We present a simple time of flight and interference model to calculate the radiated frequency and output power for the fabricated devices. We establish, theoretically, that an output power of ∼ 0.1-7 mW can be obtained from graphene/Ge wigglers with period not exceeding 85 nm, and amplitude-to-period ratio in the range of 1.4 to 10.

Liquid Crystals (LCs) are widely used in display devices, electro-optic modulators, and optical switches. A field-induced electrical conductivity modulation in pure liquid crystals is very low which makes it less preferable for direct current (DC) and radio-frequency (RF) switching applications. According to the literature, a conductivity enhancement is possible by nanoparticle doping. Considering this aspect, we reviewed published works focused on an electric field-induced conductivity modulation in carbon nanotube-doped liquid crystal composites (LC-CNT composites). A two to four order of magnitude switching in electrical conductivity is observed by several groups. Both in-plane and out-of-plane device configurations are used. In plane configurations are preferable for micro-device fabrication. In this review article, we discussed published works reporting the elastic and molecular interaction of a carbon nanotube (CNT) with LC molecules, temperature and CNT concentration effects on electrical conductivity, local heating, and phase transition behavior during switching. Reversibility and switching speed are the two most important performance parameters of a switching device. It was found that dual frequency nematic liquid crystals (DFNLC) show a faster switching with a good reversibility, but the switching ratio is only two order of magnitudes. A better way to ensure reversibility with a large switching magnitude is to use two pairs of in-plane electrodes in a cross configuration. For completeness and comparison purposes, we briefly reviewed other nanoparticle- (i.e., Au and Ag) doped LC composite’s conductivity behavior as well. Finally, based on the reported works reviewed in this article on field induced conductivity modulation, we proposed a novel idea of RF switching by LC composite materials. To support the idea, we simulated an LC composite-based RF device considering a simple analytical model. Our RF analysis suggests that a device made with an LC-CNT composite could show an acceptable performance. Several technological challenges needed to be addressed for a physical realization and are also discussed briefly.