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Strongly compensated Ga2O3 is shown to be an intrinsic (or native) p-type conductor with the largest bandgap for any reported p-type transparent semiconductor oxide which may shift the frontiers in fields such as power electronics and photonics.

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CdSe nanowires show reversible emission intensity enhancements when subjected to electric field strengths ranging from 5 to 22 MV/m. Under alternating positive and negative biases, emission intensity modulation depths of 14 ± 7% are observed. Individual wires are studied by placing them in parallel plate capacitor-like structures and monitoring their emission intensities via single nanostructure microscopy. Observed emission sensitivities are rationalized by the field-induced modulation of carrier detrapping rates from NW defect sites responsible for nonradiative relaxation processes. The exclusion of these states from subsequent photophysics leads to observed photoluminescence quantum yield enhancements. We quantitatively explain the phenomenon by developing a kinetic model to account for field-induced variations of carrier detrapping rates. The observed phenomenon allows direct visualization of trap state behavior in individual CdSe nanowires and represents a first step toward developing new optical techniques that can probe defects in low-dimensional materials.

high critical electric field of 13.2 MV/cm for Zn-doped p-type ß-Ga2O3. Materials Today Physics, (2020).

Here we report the analogous of an extremely stable topological-like ultra-wide bandgap insulator, (a solid that is a pure insulator in its bulk but has a metallic conductive surface), presenting a two-dimensional conductive channel at its surface that challenges our current thinking about semiconductor conductivity engineering. Nominally undoped epitaxial β-Ga 2 O 3 thin-films without any detectable defect (after a range of state-of-the-art techniques) showed the unexpectedly low resistivity of (3×10 -2 Ωcm) which was found to be also resistant to high dose proton irradiation (2MeV, 5x10 15 cm -2 dose) and was largely invariant (metallic) over the phenomenal temperature range of 2K up to 850K. The unique resilience and stability of the electrical properties under thermal and highly ionising radiation stressing, combined with the extended transparency range (thanks to the ultra-wide bandgap) and the already known toughness under high electrical field could open up new perspectives for use as expanded spectral range transparent electrodes (e.g. for UV harvesting solar cells or UV LEDs/lasers) as well as robust Ohmic contacts for use in extreme environments/applications and for novel optoelectronic and power device concepts.

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