SPME-GC-MS combined with PCA may be a useful method for monitoring the volatile profile characteristics of turbot during storage, which could be potentially used for freshness evaluation.

High-temperature photovoltaics (PV) for terrestrial and extraterrestrial applications have presented demanding challenges for current solar cell materials, such as Si, III−V AlGaInP, and II−VI. Widebandgap III-nitride materials, in contrast, offer several intrinsic advantages that make them extremely appealing for high-temperature applications. In this study, we fabricated and characterized III-nitride solar cells using polarization-free (i.e., nonpolar) InGaN/GaN multiple quantum wells (MQWs). The InGaN solar cells showed a large working temperature range from room temperature (RT) to 450 °C, with positive temperature coefficients up to 350 °C. The peak external quantum efficiencies of the devices showed a 2.5-fold enhancement from RT (∼32%) to 450 °C (∼81%), which is distinct from all other solar cells ever reported. This can be partially attributed to an increase of over 70% in carrier lifetime in nonpolar InGaN MQWs obtained from time-resolved photoluminescence. Furthermore, a thermal radiation analysis revealed a unique self-cooling effect for III-nitride materials, which also helps enhance device performance at high temperature. These results offer new insights and strategies for the design and fabrication of highefficiency high-temperature PV cells.

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Highly doped GaN p–n tunnel junction (TJ) contacts to InGaN solar cells are demonstrated, in which the TJs were grown by molecular beam epitaxy on top of active solar cell regions grown by metalorganic chemical vapor deposition. The effects of Si and Mg doping concentrations on solar cell characteristics are studied and used to improve turn-on voltage and series resistance. The highest doped cell with a TJ has an open-circuit voltage of 2.2 V, similar to that of the control cell fabricated using indium tin oxide (ITO), and a far less short-circuit current density loss from unwanted photogeneration in the TJ contact than in the ITO contact.

We have investigated the GaP/Si heterojunction interface for application in silicon heterojunction solar cells. We performed X-ray photoelectron spectroscopy (XPS) on thin layers of GaP grown on Si by metal organic chemical vapor deposition and molecular beam epitaxy. The conduction band offset was determined to be 0.9 ± 0.2 eV, which is significantly higher than predicted by Anderson's rule (0.3 eV). XPS also revealed the presence of Ga-Si bonds at the interface that are likely to be the cause of the observed interface dipole. Via cross-sectional Kelvin probe force microscopy (x-KPFM), we observed a charge transport barrier at the Si/GaP interface which is consistent with the high-conduction band offset determined by XPS and explains the low open-circuit voltage and low fill factor observed in GaP/Si heterojunction solar cells.

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