Traps in the spotlight: How traps affect the charge carrier dynamics in Cs₂AgBiBr₆ perovskite

Suitable optoelectronic properties of lead halide perovskites make these materials interesting semiconductors for many applications. Toxic lead can be substituted by combining monovalent and trivalent cations, such as in Cs₂AgBiBr₆. However, efficiencies of Cs₂AgBiBr₆-based photovoltaics are still...

Direct hole and delayed electron capture on a picosecond timescale by Eu2+ centers in CaGa2S4 monitored by synchroscan with horizontal blanking

A Eu2+ concentration and temperature dependent energy transfer study from the host lattice to Eu2+ luminescence centers in Ca(1–x)EuxGa2S4 (x = 0.001 to 0.05) was performed with a special streak camera that combines the high timing resolution of a conventional synchroscan operation (<2 ps) with the ability to study long lived states (10?ns???1...

Spontaneous emission control of single quantum dots in bottom-up nanowire waveguides

Nanowire waveguides with controlled shape are promising for engineering the collection efficiency of quantum light sources. We investigate the exciton lifetime in individual InAsP quantum dots, perfectly positioned on-axis of InP nanowire waveguides. We demonstrate control over the quantum dot spontaneous emission by varying the nanowire...

Position controlled nanowires for infrared single photon emission

We report the experimental demonstration of single-photon and cascaded photon pair emission in the infrared, originating from a single InAsP quantum dot embedded in a standing InP nanowire. A regular array of nanowires is fabricated by epitaxial growth on an electron-beam patterned substrate. Photoluminescence spectra taken on single quantum...

Surround-gated vertical nanowire quantum dots

We report voltage dependent photoluminescence experiments on single indium arsenide phosphide (InAsP) quantum dots embedded in vertical surround-gated indium phosphide (InP) nanowires. We show that by tuning the gate voltage, we can access different quantum dot charge states. We study the anisotropic exchange splitting by polarization analysis,...

Sharp emission from single InAs quantum dots grown on vicinal GaAs surfaces

We report on optical studies of single InAs quantum dots grown on vicinal GaAs(001) surfaces. To ensure low quantum dot density and appropriate size, we deposit InAs layers 1.4 or 1.5 ML thick, thinner than the critical thickness for Stranski–Krastanov quantum dot formation. These dots show sharp and bright photoluminescence. Lifetime...

Enhanced photoluminescence at poly(3-octyl-thiophene)/TiO2 interfaces

The photoluminescence (PL) of poly(3-octyl-thiophene) (P3OT) thin films applied on TiO2 substrates is compared to the PL of P3OT films applied on quartz. Quenching of excitons occurs at the P3OT/TiO2 interface and not at the P3OT/quartz interface. Yet, in the former case the PL intensity is stronger than in the latter. In particular, P3OT films...