Dilute nitride films with a roughly 1 eV band gap can be lattice-matched to gallium arsenide and germanium, therefore could become critical component in next-generation multijunction solar cells. To date most dilute cells have been plagued poor efficiency, due large part short diffusion lengths. This study focuses on two techniques aimed at improving the quality of grown by molecular beam epitaxy: utilization biased deflection plates installed front nitrogen plasma source, introduction...

Record high on-current of 78 <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\mu\hbox{A}/\mu\hbox{m}$</tex></formula> in a tunnel field-effect transistor (TFET) is achieved at 0.5 V room temperature. The TFET employs staggered AlGaSb/InAs heterojunction with the tunneling direction oriented in-line gate field. measured results are consistent numerical simulation device structure. Simulations...

Nonalloyed ohmic contacts regrown by molecular beam epitaxy were made on InAlN/AlN/GaN/SiC high-electron-mobility transistors (HEMTs). Transmission-line-method measurements carried out from 4 K to 350 K. Although the total contact resistance is dominated <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$\hbox{metal}/ \hbox{n}^{+}\hbox{-}\hbox{GaN}$</tex></formula> (...

The current-voltage characteristics of AlGaSb/InAs staggered-gap n-channel tunnel field-effect transistors are simulated in a geometry which the gate electric field is oriented to be same direction as junction internal field. It shown that this can also support low-voltage operation and low subthreshold swing. In absence simple analytic theory for transistor allow direct comparisons, two-dimensional numerical simulations used explore electrostatic geometrical design considerations including...

Vertical tunnel field-effect transistors (TFETs) in which the gate field is aligned with tunneling direction have been fabricated using a novel gate-recess process, resulting record on-current. The junction consists of InAs/GaSb broken band alignment. process results low drain contact and access resistances; together favorable gap heterojunction, this leads to high I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> 180 μA/μm at V...

Vertical n-channel tunnel field-effect transistors (TFETs) with tunneling normal to the gate based on an n+ In <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">∞=0.53-&gt;;1</sub> GaAs/p <sup xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> InP heterojunction have been demonstrated exhibit simultaneously a high I xmlns:xlink="http://www.w3.org/1999/xlink">ON</sub> /I xmlns:xlink="http://www.w3.org/1999/xlink">OFF</sub> ratio of 6 × 10...

We review the recent developments in GaAs-based 1.55-mum lasers grown by molecular beam epitaxy (MBE). While materials growth is challenging, window appears to be relatively broad and described detail. The key considerations for producing high-quality GalnNAsSb material emitting at regime are examined, including nitrogen plasma conditions, ion removal from flux, surfactant- mediated growth, roles of various V-II ratios, temperature, active region thermal budget, proper annealing,...

Abstract-We report Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Zln xmlns:xlink="http://www.w3.org/1999/xlink">0.53</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.47</sub> As MOSFETs having both self-aligned in situ Mo source/drain ohmic contacts and InAs n <sup xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> regions formed by MBE regrowth. The device epitaxial...

Vertical n-channel tunnel field-effect transistors (FETs) based on compound semiconductors, in a new geometry with tunneling normal to the gate, are demonstrated for first time using an n <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> In <sub xmlns:xlink="http://www.w3.org/1999/xlink">0.53</sub> Ga xmlns:xlink="http://www.w3.org/1999/xlink">0.47</sub> As/n /n ,=0.53- >;1 GaAs/p InP heterojunction. At 300 K, TFETs show on-current of ~20...

We present the first continuous-wave (CW) edge-emitting lasers at 1.5 /spl mu/m grown on GaAs by molecular beam epitaxy (MBE). These single quantum well (QW) devices show dramatic improvement in all areas of device performance as compared to previous reports. CW output powers high 140 mW (both facets) were obtained from 20 times/ 2450 ridge-waveguide possessing a threshold current density 1.06 kA/cm/sup 2/, external efficiency 31%, and characteristic temperature T/sub 0/ 139 K 10/spl...

Ti/Al/Ni/Au ohmic contacts were formed on heavily doped n+ metal-polar GaN samples with various Si doping concentrations grown by molecular beam epitaxy. The contact resistivity (RC) and sheet resistance (Rsh) as a function of corresponding free carrier concentration (n) measured. Very low RC values (&amp;lt;0.09 Ω mm) obtained, minimum 0.035 mm sample room temperature ∼5 × 1019 cm−3. Based the systematic study, role Rsh is discussed in context regrown for based high electron mobility transistors.

Results from a ridge waveguide laser diode (LD) structure, with three GaInNAs quantum wells (QWs) and GaNAs barriers, are presented. The sample was grown by solid source molecular beam epitaxy an RF plasma nitrogen source. These devices differ previously reported QWs LDs that used GaAs as the barrier material. introduction of into barriers reduces spectral blue shift caused post-growth annealing. Long wavelength emission out to 1.405 μm observed. exhibited threshold current densities low 1.5...

The boom in fiber-optic communications has caused a high demand for GaAs-based lasers the 1.3-1.6-/spl mu/m range. This led to introduction of small amounts nitrogen into InGaAs reduce bandgap sufficiently, resulting new material that is lattice matched GaAs. More recently, addition Sb allowed further reduction bandgap, leading first demonstration 1.5-/spl by authors. Additional work focused on use GaAs, GaNAs, and now GaNAsSb barriers as cladding GaInNAsSb quantum wells. We present results...

High-efficiency optical emission past 1.3 /spl mu/m of GaInNAs on GaAs, with an ultimate goal a high-power 1.55-/spl vertical-cavity surface-emitting laser (VCSEL), has proven to be elusive. While could theoretically grown lattice-matched GaAs very small bandgap, wavelengths are actually limited by the N solubility limit and high In strain limit. By adding Sb quaternary, we have observed remarkable shift toward longer luminescent while maintaining intensity. The increase in these new alloys...

The first low-threshold 1.55 µm lasers grown on GaAs are reported. Lasing at was observed from a 20×2400 as-cleaved device with room-temperature continuous-wave threshold current density of 579 A/cm2, external efficiency 41%, and 130 mW peak output power. pulsed 550 A/cm2 >600

In the past few years, GaInNAsSb has been found to be a potentially superior material both GaInNAs and InGaAsP for communications wavelength laser applications. It observed that due surfactant role of antimony during epitaxy, higher quality can grown over entire 1.2–1.6 µm range on GaAs substrates. addition, it discovered in also works as constituent significantly modifies valence band. These findings motivated systematic study alloys with widely varying compositions. Our recent progress...

We report a sharp reduction in the resistivity of Ohmic contacts using situ deposition molybdenum (Mo) onto n-type In0.53Ga0.47As grown on InP. The were formed by evaporating Mo wafer an electron beam evaporator connected to molecular epitaxy chamber under ultrahigh vacuum. Transmission line measurements showed specific contact resistivities 0.5±0.3 Ω μm2 (2.90 μm), 0.9±0.4 (4.3 and 1.3±0.4 (4.7 μm) for abrupt InAs/InGaAs heterojunctions, graded InAs/InGaAs, InGaAs films, respectively. These...

The authors report ultralow specific contact resistivity (ρc) in nonalloyed, situ Ohmic contacts to heavily doped n-type In0.53Ga0.47As:Si layers with 6×1019cm−3 active carrier concentration, lattice matched InP. were formed by depositing molybdenum (Mo) immediately after the In0.53Ga0.47As growth without breaking vacuum. Transmission line model measurements showed a of (1.1±0.6)×10−8Ωcm2 for Mo∕InGaAs interface. show no observable degradation annealing at 300 and 400°C 1min duration.

Abstract The first fabrication of a III‐V tunnel field‐effect transistor (TFET) with tunneling directed perpendicular to the gate is reported. This new geometry utilizes an InAs/Al 0.45 Ga 0.55 Sb staggered‐gap junction intended for high on current and steep subthreshold swing. measurements transport properties at room temperature ‐50 °C are provided. Tunneling confirmed by observation negative differential resistance in forward bias polarity. Transistor on‐current 21 μA/μm 0.3 V swing 830...

Low-threshold room temperature continuous wave 1.49 µm GaInNAsSb lasers are presented. Room threshold current density of 1.1 kA/cm2 was observed with a high external quantum efficiency 40% and maximum output power 30 mW from both facets.

The authors describe very low temperature (350–420°C) growth of atomically smooth Ge films (0.2–0.4nm roughness) directly on Si(100) via gas-source molecular beam epitaxy. A carefully tuned admixture (GeH3)2CH2, possessing unique pseudosurfactant properties, and conventional Ge2H6 provides unprecedented control film microstructure, morphology, composition. Formation edge dislocations at the interface ensures virtually relaxed monocrystalline (∼40–1000nm thick) with a threading dislocation...

Compact optical interconnects require efficient lasers and modulators compatible with silicon. Ab initio modeling of Ge1−xCx (x = 0.78%) using density functional theory HSE06 hybrid functionals predicts a splitting the conduction band at Γ strongly direct bandgap, consistent anticrossing. Photoreflectance Ge0.998C0.002 shows bandgap reduction supporting these results. Growth tetrakis(germyl)methane as C source no signs C-C bonds, clusters, or extended defects, suggesting highly...

Interband transitions in $\mathrm{Ga}{\mathrm{N}}_{0.02}{\mathrm{As}}_{0.98\ensuremath{-}x}{\mathrm{Sb}}_{x}∕\mathrm{Ga}\mathrm{As}$ single quantum wells (SQWs) with $0<x\ensuremath{\leqslant}0.11$ have been investigated by contactless electroreflectance (CER). CER features related to the ground and excited state observed compared those obtained from theoretical calculations, which were performed framework of effective mass formalism model. It has concluded that these SQWs are type I...