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In this work, the capacity of porous silicon (PS) machined by laser photoetching was studied as an ethanol sensor, as well as the influences of the type and the conductivity of the crystalline silicon used to obtain sensors. The resistivities used were 1–10 and 0.0014–0.004 Ω∙cm, both wafers were n-type. The response of the device was determined at room temperature (27 °C). The results can be used to appropriately select the conductivity of semiconductor materials to be used as sensors. Infrared spectroscopy confirms the absorption of ethanol in the surface of the photoetched PS. Morphological analysis revealed a macroporous structure, with pore diameters of 2.6 and 0.39 μm for the wafers of 1–10 and 0.0014–0.004 Ω∙cm respectively. The macroporous structure demonstrates a high sensibility and exhibited excellent sensing characteristics during the detection of low concentrations of ethanol. The quantity of ethanol was registered with the changes in the voltage of operation. The performance of the sensor was characterized by curves of voltage vs. time. The minimum quantity of ethanol analyzed was 1 µl. The results demonstrate that photoetched PS has the potential to develop sensitive sensors. [ABSTRACT FROM AUTHOR]

In this paper, a solar cell based on W O 3 /CdTe heterojunction was analyzed and optimized, for which the following structure of the Al/AZO/ W O 3 /CdTe/NiO/Ni device was proposed, which was numerically simulated by the SCAPS 1-D software. Using the software, the effect of the thickness and carrier concentration of the absorber layer (CdTe) and the window layer ( W O 3 ) was analyzed, and the optimal value of these parameters was found to be 2 µm and 10 15   c m − 3 for the CdTe layer and 10 nm and 10 19   c m − 3 for the W O 3 layer, respectively. The influence of the defect density of the W O 3 /CdTe interface on the performance of the proposed cell was also analyzed, simulating from 10 10 to 10 16   c m − 2 , obtaining better device performance at lower interface defect density. Another parameter analyzed was the operating temperature on the photovoltaic performance of the device, observing that the solar cell has a better performance at lower temperatures. Finally, a maximum optimized PCE of 19.87% is obtained with a Voc = 0.85 V, Jsc = 28.45 m A / c m 2 , and FF = 82.03%, which makes the W O 3 /CdTe heterojunction an interesting alternative for the development of CdTe-based solar cells. [ABSTRACT FROM AUTHOR]