High electron mobility in nearly-dislocation-free hexagonal InN

2021 ◽  
Author(s):  
Ling Chen ◽  
Shanshan Sheng ◽  
Bowen Sheng ◽  
Tao Wang ◽  
Liuyun Yang ◽  
...  
Keyword(s):  
Electron Mobility ◽  
High Speed ◽  
Room Temperature ◽  
Molecular Beam ◽  
Electronic Device ◽  
High Mobility ◽  
Hall Effect Measurement ◽  
Threading Dislocation ◽  
High Electron ◽  
Transmission Electron

Abstract We demonstrate a recorded directed-probed electron mobility of ~4850 cm2/Vs in nearly-dislocation-free hexagonal InN at room temperature by Hall-effect measurement. Those extremely high quality InN are achieved through droplet-assisted epitaxy on GaN/sapphire template by molecular beam epitaxy. They behave as crystals with diameter of several micrometers, being confirmed to be nearly free of threading dislocation by transmission electron microscopy. The achievement of such high mobility InN provides promising opportunities for fabricating high speed electronic device.

Effect of High Temperature Single and Multiple AlN Intermediate Layers on N-polar and Ga-polar GaN Grown by Molecular Beam Epitaxy

2001 ◽  
Vol 693 ◽  
Author(s):  
F. Fedler ◽  
J. Stemmer ◽  
R. J. Hauenstein ◽  
T. Rotter ◽  
A. M. Sanchez ◽  
...  
Keyword(s):  
High Temperature ◽  
Molecular Beam Epitaxy ◽  
Electron Mobility ◽  
Molecular Beam ◽  
Threading Dislocation ◽  
Electrical Measurements ◽  
Force Microscopy ◽  
Atomic Force ◽  
Intermediate Layers ◽  
Transmission Electron

AbstractWurtzite GaN samples containing one, three and five 4nm thick high temperature (HT) AlN Interlayers (IL) have been grown on (0001) sapphire substrates by plasma-assisted molecular beam epitaxy (PAMBE). N-polar as well as Ga-polar thin films have been characterized by x-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), and electrical measurements.All samples under consideration show excellent AFM rms surface roughness below 1nm. Previously, we published a reduction of the threading dislocation (TD) density by a factor of seven due to the introduction of one AlN-IL. When introducing multiple AlN-IL a reduction by a factor of 5.2 is achieved.Hall measurements show a rise in electron mobility due to possible 2DEG formation at the interface between GaN and the AlN-ILs. Significant growth mode differences between Ga-polar and N-polar samples result in drastically higher electron mobility values for N-polar material. For N-polar samples the exceptional mobility increase from 68 (no AlN-IL) to 707 cm2/Vs (one AlN-IL) as well as the extremely low intrinsic carrier density of 1 x 1017 cm-3 prove the applicability of AlN barriers in inverted FET devices.

scholarly journals High electron mobility in strained GaAs nanowires

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Leila Balaghi ◽  
Si Shan ◽  
Ivan Fotev ◽  
Finn Moebus ◽  
Rakesh Rana ◽  
...  
Keyword(s):  
Gallium Arsenide ◽  
Electron Mobility ◽  
High Performance ◽  
Room Temperature ◽  
High Mobility ◽  
Semiconductor Nanowires ◽  
Core Shell ◽  
High Electron ◽  
Bulk Crystals ◽  
Gaas Nanowires

AbstractTransistor concepts based on semiconductor nanowires promise high performance, lower energy consumption and better integrability in various platforms in nanoscale dimensions. Concerning the intrinsic transport properties of electrons in nanowires, relatively high mobility values that approach those in bulk crystals have been obtained only in core/shell heterostructures, where electrons are spatially confined inside the core. Here, it is demonstrated that the strain in lattice-mismatched core/shell nanowires can affect the effective mass of electrons in a way that boosts their mobility to distinct levels. Specifically, electrons inside the hydrostatically tensile-strained gallium arsenide core of nanowires with a thick indium aluminium arsenide shell exhibit mobility values 30–50 % higher than in equivalent unstrained nanowires or bulk crystals, as measured at room temperature. With such an enhancement of electron mobility, strained gallium arsenide nanowires emerge as a unique means for the advancement of transistor technology.

scholarly journals The frontiers of functionalized graphene-based nanocomposites as chemical sensors

2021 ◽  
Vol 10 (1) ◽  
pp. 330-369
Author(s):  
Norizan M. Nurazzi ◽  
Norli Abdullah ◽  
Siti Z. N. Demon ◽  
Norhana A. Halim ◽  
Ahmad F. M. Azmi ◽  
...  
Keyword(s):  
Electron Mobility ◽  
Room Temperature ◽  
Chemical Sensor ◽  
Performance Enhancement ◽  
Ballistic Transport ◽  
Quantum Hall ◽  
Single Atom ◽  
Research Progress ◽  
Thick Sheet ◽  
High Electron

Abstract Graphene is a single-atom-thick sheet of sp2 hybridized carbon atoms that are packed in a hexagonal honeycomb crystalline structure. This promising structure has endowed graphene with advantages in electrical, thermal, and mechanical properties such as room-temperature quantum Hall effect, long-range ballistic transport with around 10 times higher electron mobility than in Si and thermal conductivity in the order of 5,000 W/mK, and high electron mobility at room temperature (250,000 cm2/V s). Another promising characteristic of graphene is large surface area (2,630 m2/g) which has emerged so far with its utilization as novel electronic devices especially for ultrasensitive chemical sensor and reinforcement for the structural component applications. The application of graphene is challenged by concerns of synthesis techniques, and the modifications involved to improve the usability of graphene have attracted extensive attention. Therefore, in this review, the research progress conducted in the previous decades with graphene and its derivatives for chemical detection and the novelty in performance enhancement of the chemical sensor towards the specific gases and their mechanism have been reviewed. The challenges faced by the current graphene-based sensors along with some of the probable solutions and their future improvements are also being included.

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