The sensors in modern smartphones are a promising and cost-effective tool for experimentation physics education, but many experiments face practical problems. Often the phone is inaccessible during experiment data usually needs to be analyzed subsequently on computer. We address both problems by introducing new app, called 'phyphox', which specifically designed utilizing teaching. app free offer same set of features Android iOS.

The mosaicity of GaN layers grown by metalorganic vapor phase epitaxy, on (0001) sapphire and exhibiting different grain diameters is studied using high-resolution x-ray diffraction. coherence lengths, the tilt, twist mosaic structure are determined utilizing data taken in scattering geometries. results models, which were applied, then compared discussed. dislocation densities, obtained from data, with plan-view transmission electron microscopy atomic force microscopy.

High-resolution x-ray diffraction has been used to analyze the type and density of threading dislocations in (001)-oriented GaN epitaxial layers. For this, (00l) (hkl) Bragg reflections with h or k nonzero were studied, latter one measured skew symmetric geometry. The defect analysis was applied a variety layers grown by molecular-beam epitaxy under very different conditions. outcome is fundamental correlation between densities edge- screw-type dislocations.

The formation of dislocations and stress in GaN layers grown by metalorganic vapor phase epitaxy on sapphire is investigated with regard to the average grain diameter. diameter was determined monitoring high-temperature island coalescence process during growth using reflectometry. It found that density edge threading decreases compressive measured after cooling room temperature increases when thickness increase. data are consistent models development tensile due growth.

Relaxation of tensile strain in AlxGa1−xN layers different compositions epitaxially grown on GaN/sapphire is investigated. Extended crack channels along 〈211¯0〉 directions are formed if the aluminum content exceeds a critical value, which decreases with increasing layer thickness. This process found to limit average energy density maximum value 4 J/m2. By calculating stress distribution between cracks and release rate for propagation, relaxed as measured by x-ray diffraction correlated...

We report on the incorporation of In during growth InxGa1−xN by molecular beam epitaxy under varying In/Ga flux ratios and with different film thicknesses. The efficiency studied energy dispersive x-ray microanalysis, high-resolution diffraction photoluminescence spectroscopy is strongly affected chosen fluxes Ga N limited excess nitrogen compared to gallium. Furthermore, thick films exhibit a decrease content in direction. behavior can be explained considering stabilities two binary...

Migration enhanced epitaxy has been applied to induce the change from two-dimensional growth formation of self-assembling islands in CdSe on ZnSe. Transmission electron microscopy images samples with a ZnSe caplayer show transition flat quantum well an interrupted layer pronounced thickness fluctuations when exceeds its critical thickness. These results are confirmed by high resolution x-ray diffraction measurements, as only for former sample 004 rocking curve can be simulated assuming...

Abstract In order to extend the available sensors of smartphone experiments with cheap microcontroller-based external sensors, experimentation app ‘phyphox’ has been extended a generic Bluetooth Low Energy interface. Since its application requires an in-depth understanding underlying technologies, direct use that interface for educational purposes is limited. To avoid this difficulty, functionality was encapsulated into Arduino and MicroPython library. With these, also educators learners...

The type and density of threading dislocations in GaN epitaxial layers grown on c-plane sapphire have been analyzed by using nondestructive high resolution X-ray diffraction. highly distorted were described as mosaic crystals characterized a mean tilt twist angle between the blocks which are correlated with densities screw edge dislocations, respectively. Triple axis rocking curves (00l) reflections for varying l-indices used to determine angle, while was extrapolated from ω-scans (hkl)...

We present optical investigations on CdTe/(CdMg)Te single quantum wells (QWs) and demonstrate the high structural quality of pseudomorphic grown QWs structure which shows photoluminescence efficiency up to room temperature. Due large band-gap difference between CdTe Cd0.51Mg0.49Te more than 0.8 eV remarkable strong confinement effects are observable. A enhancement exciton binding energies is found by decreasing well width. In 50-Å-wide QW energy two times larger compared with that bulk CdTe....

Lattice relaxation of strained AlxGa1−xN/GaN superlattices grown on thick GaN buffer layers is investigated using optical microscopy, x-ray diffraction, and photoluminescence spectroscopy. The results are compared to bulk AlxGa1−xN particularly with regard the impact superlattice period Al content. A process which keeps coherency between barriers wells in found it attributed misfit dislocations at buffer/superlattice interface. Additionally, relax via crack channels form beyond a critical...

We propose an easy experiment that allows students to determine the speed of sound through a simple time-of-flight measurement using two smartphones. The concept sensors in mobile phones for physics experiments has become well-known option science teachers. Since these devices are readily available most and teachers, can be set up at little no cost while generating fascination motivation thanks novelty their own unusual way. From all modern phones, microphone offers best temporal resolution...

Using migration enhanced epitaxy the self-organized formation of CdSe islands on ZnSe in open and overgrown structures has been studied by transmission electron microscopy, high-resolution X-ray diffraction, atomic force photoluminescence excitation spectroscopy. The transition from homogeneous quantum wells with flat interfaces to fluctuating films could be observed when exceeding critical thickness. These interrupted layers contain dots embedded Cd1—xZnxSe a concentration gradient. Islands...

The influence of the growth conditions during capping CdSe/ZnSe quantum structures grown on GaAs(001) by molecular-beam epitaxy (MBE) were systematically investigated high-resolution x-ray diffraction, transmission electron microscopy, and temperature dependent, partly time-resolved photoluminescence spectroscopy. results clearly indicate formation wells with potential fluctuations if conventional MBE is used for CdSe ZnSe. In contrast, dot occurs using migration enhanced this step. latter...

High-resolution X-ray diffraction has been used to analyze GaN epilayers with varying coalescence thickness which were grown by MOVPE on (0001) oriented sapphire. The decrease of the density edge type threading dislocations increasing causes a marked difference in mosaicity samples. As defects form along grain boundaries, this corresponds an increase lateral coherence length thickness. obtained from simulations reciprocal lattice points off-axis Bragg reflections, measured asymmetric geometry.

The semimagnetic semiconductors ${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}\mathrm{\ensuremath{-}}\mathit{y}}$${\mathrm{Mn}}_{\mathit{x}}$${\mathrm{Mg}}_{\mathit{y}}$Te grown by molecular-beam epitaxy have been studied photoluminescence and excitation spectroscopy. It is shown that the Zeeman splittings of exciton states depend on Mn content only are independent Mg content, i.e., carrier--Mn spin-exchange constants not affected incorporation. Exciton magnetic polarons using method...

ZnSe-based laser diodes with emission wavelength from 500 to 560 nm are studied. The long operation of these requires careful optimization the CdZnSSe quantum well material. It is shown that under stoichiometric growth conditions wells high optical and structural qualtity can be realized. Employed in structures room-temperature cw-operation around obtained. In comparison emitting at 505 it found Cd content does not degrade operational characteristics devices. pulsed mode more than 1100 mW...

CdSe/ZnSe quantum structures grown on GaAs(001) by molecular-beam epitaxy were systematically investigated high-resolution x-ray diffraction and transmission-electron microscopy. Half of the initial Cd deposit redesorbs when migration-enhanced is used instead conventional for overgrowth CdSe ZnSe. This result explained a segregation model accounting an enhanced redesorption due to replacement Zn in topmost surface layers. The observed intermixing can be this model.

The thermal behavior of Mg-doped and intentionally undoped bulk crystals homoepitaxial GaN was investigated in a wide temperature range from 12 to 600 K. With high-resolution x-ray diffraction, both lattice parameters c were determined the expansion coefficients calculated. Within experimental accuracy, mean values extracted for ranges 12–100, 100–250, 250–600 These are essential, especially, interpretation measurements other properties performed at low temperatures.