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Abstract: Photovoltaic solar cells based on the intermediate band (IB) concept could greatly enhance the efficiency of future devices. We have analyzed the electrical and photoconductivity properties of GaP supersaturated with Ti to assess its suitability for IB solar cells. GaP:Ti was obtained by ion implantation followed by pulsed‐laser melting (PLM) using an ArF excimer laser. It was found that PLM energy densities between 0.35 and 0.55 J/cm2 produced a good recovery of the crystalline structure of GaP (both unimplanted and implanted with Ti), as evidenced by high mobility measured values (close to the reference GaP). Outside this energy density window, the PLM failed to recover the crystalline structure producing a low mobility layer that is electrically isolated from the substrate. Spectral photoconductivity measurements were performed by using the van der Pauw set up. For GaP:Ti a significant enhancement of the conductivity was observed when illuminating the sample with photon energies below 2.26 eV, suggesting that this photoconductivity is related to the presence of Ti in a concentration high enough to form an IB within the GaP bandgap. The position of the IB was estimated to be around 1.1 eV from the conduction band or the valence band of GaP, which would lead to maximum theoretical efficiencies of 25% to 35% for a selective absorption coefficients scenario and higher for an overlapping scenario. [ABSTRACT FROM AUTHOR]

Power ultrasound-assisted crystallization, which is also called sonocrystallization, is a novel and effective method for enhancing crystallization processes compared to conventional processes. In both supercooled and supersaturated crystallization, power ultrasound can accelerate the nucleation rate and better control the formation and growth of crystals. Due to its high efficiency, power ultrasound has been applied in many fields. In this review, studies published in recent years on effects of power ultrasound in both supercooled and supersaturated crystallization processes are discussed, with focus on the widely accepted crystallization mechanism and modeling. The applications of power ultrasound in liquid ice crystallization, ice cream manufacture, fruit and vegetable preservation and sugar and food supersaturated crystallization are summarized, and challenges and trends for further development of the technology are presented. [ABSTRACT FROM AUTHOR]