We report on the growth and electronic properties of polycrystalline III-V semiconductors, which to date have not been discussed in depth in the literature. III-V polycrystalline semiconductor thin films were grown by metalorganic vapour phase epitaxy in the temperature range 410°C-475°C, which is compatible for integration into the Back-End-Of-Line (BEOL) silicon based integrated circuits. The thickness of the films in this study is in the range of tens to a few hundreds of nanometers, and deposited on amorphous substrates (either smart-phone-grade glass or Si/SiO 2 ) and, also, on oxidised GaAs epi-ready wafers. Extensive AFM, SEM and TEM analyses show interlinked-to-continuous polycrystalline III-V films based on In(Al)As or GaSb. Hall-van der Pauw measurements return results of high mobility and controllable charge density for n-and p-type field effect transistors. In the GaAs/In(Al)As system, electron density ranging from 1×10 16 to 1×10 19 cm −3 (n) was achieved, with room temperature mobility values in the range of 100-150 cm 2 V −1 s −1 and hole mobility values in the range of 1-10 cm 2 V −1 s −1 have been measured in Zn doped samples. Polycrystalline GaSb films demonstrated p-type behaviour (1×10 17 cm −3 ) with remarkably high room temperature hole mobility values up to 66 cm 2 V −1 s −1 for the films grown on Si/SiO 2 substrate (and 300 cm 2 V −1 s −1 for the GaAs substrate where an epitaxial process is actually in place). Materials could be stacked into heterostructures, providing a promising platform for complex devices enabling compatible n-and phetero-layers for 3D integration formed at temperatures 480°C.

Polycrystalline indium arsenide (poly InAs) thin films grown at 475 °C by metal organic vapor phase epitaxy (MOVPE) are explored as possible candidates for low-temperature-grown semiconducting materials. Structural and transport properties of the films are reported, with electron mobilities of ~100 cm2/V·s achieved at room temperature, and values reaching 155 cm2/V·s for a heterostructure including the polycrystalline InAs film. Test structures fabricated with an aluminum oxide (Al2O3) top-gate dielectric show that transistor-type behavior is possible when poly InAs films are implemented as the channel material, with maximum ION/IOFF > 250 achieved at −50 °C and ION/IOFF = 90 at room temperature. Factors limiting the ION/IOFF ratio are investigated and recommendations are made for future implementation of this material.

Improvements in the spatial resolution of synchrotron-based X-ray probes have reached the nano-scale and they, nowadays, constitute a powerful platform for the study of semiconductor nanostructures and nanodevices that provides high sensitivity without destroying the material. Three complementary hard X-ray synchrotron techniques at the nanoscale have been applied to the study of individual nanowires (NWs) containing non-polar GaN/InGaN multi-quantum-wells. The trace elemental sensitivity of X-ray fluorescence allows one to determine the In concentration of the quantum wells and their inhomogeneities along the NW. It is also possible to rule out any contamination from the gold nanoparticle catalyst employed during the NW growth. X-ray diffraction and X-ray absorption near edge-structure probe long- and short-range order, respectively, and lead us to the conclusion that while the GaN core and barriers are fully relaxed, there is an induced strain in InGaN layers corresponding to a perfect lattice matching with the GaN core. The photoluminescence spectrum of non-polar InGaN quntum wells is affected by strain and the inhomogeneous alloy distribution but still exhibits a reasonable 20% relative internal quantum efficiency.

We present a non-resonant Raman spectroscopy study of individual ZnO nanowires mediated by Au nanorod surface plasmons.