We demonstrate that GaAs-based HBTs with very low base currents at both low and high injection levels can be achieved using either Al0.35Ga0.65As or InGaP in the emitter with the proper optimization of structure and growth. We observe an order of magnitude reduction in space charge recombination current as the Al composition, and hence the energy-gap, of the emitter increases from 25% (1.77 eV)...

We have carried out direct measurements of the absolute recombination rate coefficients of four charge states of tungsten in the range from W to W in a heavy ion storage ring. We find that the rich atomic fine structure of the open f -shell leads to very high resonant enhancement of the recombination rate at energies below ∼50 eV. Even in the higher energy domain relevant to fusion plasma this ...

The photoinduced reduction of three Co electrocatalysts immobilised on TiO2 is 10(4) times faster than the reverse charge recombination. Both processes show an exponential dependence on the distance between the semiconductor and the catalytic core.

Overall photocatalytic water splitting is one of the most sought after processes for sustainable solar-to-chemical energy conversion. The efficiency of this process strongly depends on charge carrier recombination and interaction with surface adsorbates at different time scales. Here, we investigated how hydration of TiO2 P25 affects dynamics of photogenerated electrons at the millisecond to mi...

We report the charge transfer dynamics for CdSe quantum dot (QD) sensitized solar cells. The effect of QD sensitization mode in recombination kinetics has been measured and their implications in solar cell performance analyzed.

A new series of multi-modular donor-acceptor systems capable of exhibiting photoinduced charge separation have been designed, synthesized and characterized using various techniques. In this series, the electron donor was a BF2-chelated dipyrromethene (BODIPY) appended with two styryl linkers carrying two electron rich triphenylamine or phenothiazine entities. Fulleropyrrolidine linked at the me...

Doped and undoped ZnS semiconductor nanocrystals having different recombination pathways are explored to study the charge transfer reaction between the nanocrystals and the 4-nitrophenol/sodium borohydride redox couple.

Visible light-induced charge transfer dynamics were investigated in a novel transition metal triad acceptor-chromophore-donor, (NDI-phen)Pt(II)(-C≡C-Ph-CH2-PTZ)2 (1), designed for photoinduced charge separation using a combination of time-resolved infrared (TRIR) and femtosecond electronic transient absorption (TA) spectroscopy. In 1, the electron acceptor is 1,4,5,8-naphthalene diimide (NDI), ...

Previous studies of solid-state tetracyanobenzene-based donor-acceptor complexes showed that these materials were highly susceptible to both laser and mechanical damage that complicated the analysis of their electron-transfer kinetics. In this paper, we characterize the optical properties of a pyrene/tetracyanoquinodimethane charge-transfer crystal that is much more robust than the tetracyanobe...

Silicon dioxide (SiO2) has played a critical role in the development of high-efficiency silicon (Si)-based photovoltaic devices. Recently, it experienced renaissance as an interlayer many new contact passivating structures. Studies have extensively investigated recombination process at Si–SiO2 interface, however, only little is known about impact temperature on surface recombination. In this st...