We have studied the low temperature photoluminescence ~PL! of a d-doped ZnSe:~Te,N! system using two different types of samples, one with single d layers separated by undoped spacers and the other with three adjacent d layers in each doping cycle. We have concluded that both Te and N participate in radiative recombination. We observe a relatively low PL efficiency ~compared to samples without N...

Recombination in single quantum well and multiquantum well InGaN/GaN structures is studied using time-resolved photoluminescence and pulsed photoluminescence measurements. Room-temperature measurements show a rapid lifetime ~0.06 ns! for a single quantum well structure, while an increasingly long decay lifetime is measured for multiquantum wells as more quantum wells are incorporated into the s...

Back-contact perovskite solar cells offer a significant potential to reach high efficiency due reduced parasitic absorption from the top surface. However, currently reported efficiencies are considerably lower (<10%) than planar (>20%). Herein, back-contact fabricated study loss mechanisms that cause low device efficiency. This work spatially resolves short-circuit current, open-circuit voltage...

Photoluminescence lifetimes have been measured at room temperature as a function of carrier density in ZnCdSe/ZnSSe quantum wells. We show that, at low carrier density (5310 – 5 310 cm), nonradiative recombination dominates, while radiative recombination becomes more dominant as the carrier density is increased from 5310 to 5310 cm. Above ;5 310 cm, band filling effects are shown to produce a s...

For a GaAs filled metallic hole array on a pre-epi GaAs substrate, the free carriers, generated by three-photon absorption (3PA) assisted by strongly enhanced local fields, reduce the refractive index of GaAs in ~200-nm thick active area through band filling and free carrier absorption. Therefore, the surface plasma wave (SPW) resonance, and the related second harmonic (SH) spectrum blue shifts...

The large diffusion lengths recurrently measured in perovskite single crystals and films signal small bulk nonradiative recombination flux and locate the dominant carrier recombination processes at the outer interfaces. Surface recombination largely determines the photovoltaic performance, governing reductions under short-circuit current and open-circuit voltage. Quantification of recombination...

AlGaInP/GaInP multiple quantum well laser structure was grown by low-pressure metalorganic chemical vapor deposition with tertiarybutylarsine and tertiarybutylphosphine. Photoluminescence (PL) measurements were performed from 10 to 230K. The PL energy increased with temperature from 10 to 70K and decreased above 70K. The former was attributed to thermal activation of trapped carriers due to loc...

mined by the thermal distribution. With increasing temperature, the broadening of the distribution function increases. In addition, the spectrum shifts to longer wavelengths due to the temperature dependence of the bandgap. The magnitude of the emission decreases with increasing temperature due to the dominance of nonradiative recombination processes. We also measured the temperature dependence...

Time-correlated single photon counting methods are used with confocal microscopy and maximum likelihood estimation analysis to obtain fluorescence lifetime trajectories for single quantum dots with KHz update rates. This technique reveals that control of the solution environment can influence both radiative (k(rad)) and nonradiative (k(nonrad)) pathways for electron-hole recombination emission ...

Perovskite solar cells (PSCs) with a light-harvesting three-dimensional perovskite bulk layer as backbone component have achieved great progress in performance. Nonradiative recombination is one major place to improve efficiency and stability they cause significant energy loss PSCs. Additionally, an imperfection grain boundaries will initiate device degradation. One of the most successful strat...