Phase separation and thermal crystallization of SiO/SiO2 superlattices results in ordered arranged silicon nanocrystals. The preparation method which is fully compatible with Si technologies enables independent control particle size as well density spatial position by using a constant stoichiometry the layers. Transmission electron microscopy investigations confirm samples an upper limit nanocrystal sizes 3.8, 2.5, 2.0 nm without decreasing for smaller sizes. nanocrystals show strong...

Abstract Copper‐oxide compound semiconductors provide a unique possibility to tune the optical and electronic properties from insulating metallic conduction, bandgap energies of 2.1 eV infrared at 1.40 eV, i.e., right into middle efficiency maximum for solar‐cell applications. Three distinctly different phases, Cu 2 O, 4 O 3 , CuO, this binary semiconductor can be prepared by thin‐film deposition techniques, which differ in oxidation state copper. Their material as far they are known...

We present a simple method for the elimination of cracks in GaN layers grown on Si (111). Cracking usually occurs due to large lattice and thermal mismatch when layer thicknesses exceeds approximately 1 µm. By introducing thin, low-temperature AlN interlayers, we could significantly reduce crack density layer. The is practically reduced zero from an original 240 mm -2 corresponding crack-free regions 3×10 -3 2 . Additionally with low temperature full width at half maximum X-ray (2024)...

We report on GaN n-type doping using silane, germane, and isobutylgermane as Si Ge dopants, respectively. A significant increase in tensile stress during growth is observed for doped samples while this not the case doping. In addition, can be up to 2.9 × 1020 cm−3, leads 3-D already at concentrations around 1.9 1019 cm−3. The free carrier concentration was determined by Hall-effect measurements, crystal quality, structural properties x-ray diffraction measurements. Additionally, secondary...

The interplay between band gap renormalization and filling (Burstein-Moss effect) in n-type wurtzite GaN is investigated. For a wide range of electron concentrations up to $1.6\ifmmode\times\else\texttimes\fi{}{10}^{20}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$ spectroscopic ellipsometry photoluminescence were used determine the dependence energy Fermi edge on density. dominating effect an density about...

Annealing of amorphous Si/SiO2 superlattices produces Si nanocrystals. The crystallization has been studied by transmission electron microscopy and x-ray analysis. For a layer thinner than 7 nm, nearly perfect nanocrystals are found. thicker layers, growth faults dislocations exist. Decreasing the a-Si thickness increases inhomogeneous strain one order magnitude. origin in crystallized structure is discussed. temperature rapidly with decreasing thickness. An empirical model that takes into...

Thick, entirely crack-free GaN-based light-emitting diode structures on 2 in. Si(111) substrates were grown by metalorganic chemical-vapor deposition. The ∼2.8-μm-thick structure was using a low-temperature AlN:Si seed layer and two interlayers for stress reduction. In current–voltage measurements, low turn-on voltages series resistance of 55 Ω observed vertically contacted diode. By in situ insertion SixNy mask, the luminescence intensity is significantly enhanced. A light output power 152...

GaN-on-silicon is a low-cost alternative to growth on sapphire or SiC. Today epitaxial usually performed Si(111), which has threefold symmetry. The of single crystalline GaN Si(001), the material complementary metal oxide semiconductor (CMOS) industry, more difficult due fourfold symmetry this Si surface leading two differently aligned domains. We show that breaking achieve can be performed, e.g. by off-oriented substrates device quality layers. Furthermore, an exotic orientation for...

Al In N ∕ Ga heterostructures have been proposed to possess advantageous properties for field-effect transistors (FETs) over AlGaN∕GaN [Kuzmík, IEEE Electron Device Lett. 22, 501 (2001); Yamaguchi et al., Phys. Status Solidi A 188, 895 (2001)]. major advantage of such structures is that AlInN can be grown lattice-matched GaN while still inducing high charge carrier densities at the heterointerface around 2.7×1013cm−3 by differences in spontaneous polarization. Additionally, it offers a...

The authors present a detailed study of Al1−xInxN layers covering the whole composition range 0.09<x<1. All were grown on GaN Si(111) templates using metal-organic vapor phase epitaxy. For 0.13<x<0.32 samples grow fully strained and without separation. At higher In concentrations, crystalline quality starts to deteriorate transition three-dimensional growth is observed. A comparison their experimental data with theoretically predicted diagrams reveals that biaxial...

We report on III-Nitride blue light emitting diodes (LEDs) comprising a GaN-based tunnel junction (TJ) all realized by metalorganic vapor phase epitaxy in single growth process. The TJ grown atop the LED structures consists of Mg-doped GaN layer and subsequently highly Ge-doped GaN. Long thermal annealing 60 min at 800 °C is important to reduce series resistance LEDs due blockage acceptor-passivating hydrogen diffusion through n-type doped top layer. Secondary ion mass spectroscopy...

GaN growth on Si is very attractive for low-cost optoelectronics and high-frequency, high-power electronics. It also opens a route towards an integration with Early attempts to grow suffered from large lattice thermal mismatch the strong chemical reactivity of Ga at elevated temperatures. The latter problem can be easily solved using gallium-free seed layers as nitrided AlAs AlN. key device structure leading cracks layer thicknesses above 1 μm. Meanwhile, several concepts strain engineering...

Thin low-temperature AlN interlayers can be applied to reduce stress grow thick crack-free AlGaN layers on GaN buffer sapphire and Si. The mechanism leading reduction is investigated by high resolution x-ray diffractometry measurements metalorganic chemical vapor phase epitaxy grown samples Si(111) with different interlayer deposition temperatures. A decrease of tensile decreasing growth temperature observed. From reciprocal space maps we conclude that at temperatures are pseudomorphic,...

We present an electroluminescence test structure which consists of InGaN/GaN multiquantum well as active region on the top AlGaN/GaN multilayer grown by metalorganic vapor phase epitaxy Si(111) substrate. The integral room-temperature spectrum reveals a peak emission wavelength 467 nm and significantly higher brightness than identical reference sapphire In microelectroluminescence imaging, two peaks at 465 476 can be separated originating from locally different areas diode....

GaN growth on heterosubstrates usually leads to an initially high dislocation density at the substrate/seed layer interface. Due initial from small crystallites, tensile stress is generated coalescence boundaries during growth. In addition, with thermal this cracking of Si and SiC substrates when cooling room temperature. By partially masking typically applied AlN seed Si(111) in situ deposited SiN mask a reduction can be achieved for subsequently grown layer. Additionally, 6 K band edge...

A doping approach for p-type ZnO is reported which reproducible and long-time stable. For the zinc oxide layers were doped simultaneously with nitrogen arsenic in metal organic vapor phase epitaxy. The conductivity type of was investigated by scanning capacitance microscopy, a technique based on local capacitance-voltage analysis (C-V) submicron spatial resolution. Depending growth parameters, largely extended domains observed, surrounded n-type regions. differences are directly correlated...

GaN based epitaxy on silicon usually requires strain-engineering methods to avoid tensile stress after cooling from growth temperature. Silicon doping of induces additional during originating edge dislocation climb. Especially in the GaN-on-Si case high stresses for highly Si-doped layers limit freedom device design and performance. We show that germanium does not influence strain evolution enables thick n-type doped crack-free silicon. It is concluded climb originate surface roughening but...

A detailed discussion of the optical properties Al-rich Al 1− x In N alloy films is presented. The (0 0 1)-oriented layers with contents between = 0.143 and 0.242 were grown by metal-organic vapour phase epitaxy on thick GaN buffers. Sapphire or Si(1 1 1) served as substrate. High-resolution x-ray diffraction revealed pseudomorphic growth nearly lattice-matched alloys; data analysis yielded composition well in-plain strain. complex dielectric function (DF) 10 eV was determined from...

Abstract GaN growth on silicon has recently found its way into products as transistor devices for high frequencies and high‐voltage applications well light emitting diodes (LEDs). Here, we present the importance of quality layers growing LED structures transistors silicon. The major difference is that substrates suffers from edge type dislocations during doping while FETs suffer a lowered breakdown field. We will show latter most likely originating in screw dislocations. By optimizing...

We present a comprehensive overview of the optical properties zinc-blende GaN. By variety different methods, such as temperature-dependent photoluminescence, photoluminescence excitation spectroscopy, photoreflectance, and ellipsometry, we investigate its emission absorption related characteristics. The sample under study is nearly strain-free epitaxial layer grown on freestanding cubic SiC. light-hole/heavy-hole exciton was found at $3.271\phantom{\rule{0.16em}{0ex}}\mathrm{eV}$...

Despite the fact that metastable $\ensuremath{\alpha}$-Ga${}_{2}$O${}_{3}$ becomes increasingly interesting for applications in $e.g.$ high-power electronics, its basic material properties remain unclear. The authors employ plasma-assisted molecular-beam epitaxy to grow $r$-plane-oriented thin films of this birefringent semiconductor, as crystal orientation allows measurement anisotropic optical properties. firm knowledge these device design proceed, including band-gap engineering by...

Nanomechanical resonators realized from tensile-strained materials reach ultralow mechanical dissipation in the kHz to MHz frequency range. Tensile-strained crystalline that are compatible with epitaxial growth of heterostructures would thereby at same time allow realizing monolithic free-space optomechanical devices, which benefit stability, ultrasmall mode volumes, and scalability. In our work, we demonstrate nanomechanical string trampoline made InGaP, is a material epitaxially grown on...