Huili Grace Xing

Learn More
The transport properties of carriers in semiconducting graphene nanoribbons are studied by comparing the effects of phonon, impurity, and line-edge roughness scattering. It is found that scattering from impurities located at the surface of nanoribbons and from acoustic phonons are as important as line-edge roughness scattering. The relative importance of(More)
Terahertz technology promises myriad applications including imaging, spectroscopy and communications. However, one major bottleneck at present for advancing this field is the lack of efficient devices to manipulate the terahertz electromagnetic waves. Here we demonstrate that exceptionally efficient broadband modulation of terahertz waves at room(More)
Ohmic regrowth by molecular beam epitaxy (MBE) has been investigated for metal-face InAlN/AlN/GaN high electron mobility transistors (HEMTs) for the first time. Using SiO2 mask nþ-GaN was regrown in the source/drain region while deposition on the mask was lifted off in buffered HF after regrowth. The lowest contact resistance measured was 0.40 0.23Vmm by(More)
The single particle tunneling in a vertical stack consisting of monolayers of two-dimensional semiconductors is studied theoretically, and its application to a novel Two-dimensional Heterojunction Interlayer Tunneling Field Effect Transistor (Thin-TFET) is proposed and described. The tunneling current is calculated by using a formalism based on the(More)
Graphene nanoribbons !GNRs" were fabricated by metal mask lithography and plasma etching. GNRs with width #20 nm show field-effect conductance modulation of #12 at room temperature and !106 at 4.2 K. Conductance quantization due to quantum confinement in low field transport was observed. Landauer formula was utilized to fit the experimental data and(More)
Nonalloyed ohmic contacts regrown by molecular beam epitaxy were made on InAlN/AlN/GaN/SiC high-electronmobility transistors (HEMTs). Transmission-line-method measurements were carried out from 4 K to 350 K. Although the total contact resistance is dominated by the metal/n-GaN resistance (∼0.16 Ω · mm), the resistance induced by the interface between the(More)
| In this paper, we examine graphene as a material for reconfigurable terahertz (THz) optoelectronics. The ability of electrically tuning its optical properties in a wide range of THz frequencies, together with its 2-D nature and facile integration, leads to unique opportunities for inventing novel THz devices as well as for extending the performance of(More)
To deposit an ultrathin dielectric onto WSe2, monolayer titanyl phthalocyanine (TiOPc) is deposited by molecular beam epitaxy as a seed layer for atomic layer deposition (ALD) of Al2O3 on WSe2. TiOPc molecules are arranged in a flat monolayer with 4-fold symmetry as measured by scanning tunneling microscopy. ALD pulses of trimethyl aluminum and H2O nucleate(More)
The large electronic polarization in III-V nitrides allows for novel physics not possible in other semiconductor families. In this work, interband Zener tunneling in wide-band-gap GaN heterojunctions is demonstrated by using polarization-induced electric fields. The resulting tunnel diodes are more conductive under reverse bias, which has applications for(More)