Single photons produced by fundamentally dissimilar physical processes will in general not be indistinguishable. We show how photons produced from a quantum dot and by parametric down-conversion in a nonlinear crystal can be manipulated to be indistinguishable. The measured two-photon coalescence probability is 16%, and is limited by quantum-dot decoherence. Temporal filtering to the quantum-dot coherence time and accounting for detector time response increases this to 61% while retaining 25% of the events. This technique can connect different elements in a scalable quantum network.

Atomically thin transition metal dichalcogenides (TMDs) are ideal candidates for ultrathin optoelectronics that are flexible and semitransparent. Photodetectors based on TMDs show remarkable performance, with responsivity and detectivity higher than 10 ³ AW ⁻¹ and 10 ¹² Jones, respectively, but they are plagued by response times as slow as several tens of seconds. Although it is well established that gas adsorbates such as water and oxygen create charge traps and significantly increase both the responsivity and the response time, the underlying mechanism is still unclear. Here we study the influence of adsorbates on MoS ₂ photodetectors under ambient conditions, vacuum and illumination at different wavelengths. We show that, for wavelengths sufficiently short to excite electron-hole pairs in the MoS ₂ , light illumination causes desorption of water and oxygen molecules. The change in the molecular gating provided by the physisorbed molecules is the dominant contribution to the device photoresponse in ambient conditions.

The crystallization of monosodium urate monohydrate (MSU) in the synovial fluid has long been associated with the joint disease gout, which is characterized by recurring attacks of pain and inflammation within the joints. In this work, in situ atomic force microscopy (AFM) on single crystal (010) MSU surfaces and dynamic light scattering were used complementarily to investigate the growth of MSU in 2–10 mM urate solutions under model physiological conditions (37 °C, pH = 7.4, 150 mM NaCl). In this solution regime, crystal growth rates normal to the (010) surface followed the square of supersaturation, which is consistent with a two-dimensional island nucleation and spread mechanism. Islands observed under in situ AFM imaging conditions had sizes consistent with dynamic light scattering measurements but exhibited unique faceting not typically observed in fully developed crystals or predicted by previous theoretical work. Preferred alignment of the islands' long axis and the underlying ±c axis of the MSU (010) was observed, as was island overgrowth over time.