Improving Humidity Sensing of Black Phosphorus Nanosheets by Co-Doping Benzyl Viologen and Au Nanoparticles

Black phosphorus (BP) is a two-dimensional and layered elemental semiconductor that is very sensitive to the subtle fluctuation of relative humidity (RH). However, the practical application of BP material was undesirably plagued by the irreversible degradation under moisture/oxygen atmospheres. To circumvent this limitation, here we prepared BP co-doped with benzyl viologen (BV) and Au nanoparticles as the sensing layer and explored the humidity-sensing performance at room temperature (20 oC). Unlike BP (BP-BV) counterparts, BP-Au (BP-BV-Au) sensors demonstrated unvaried response polarity with increasing RH. And BV introduction improved the recovery characteristics. Additionally, the ternary BP-BV-Au sensors delivered decent selectivity and negligible hysteresis. On the one hand, the in situ reduction of Au nanoparticles consumed lone electron pairs within BP, suppressed the interaction with ambient moisture/oxygen, and improved the operation stability and recovery. On the other hand, hydrophobic BV as the protection layer further hindered water attachment. This co-doping behavior reduced the hole density and ensured the predominant interaction between low-energy sorption sites within BP and water molecules, thus leading to a larger resistance modulation (i.e., stronger response) and quicker reaction kinetics. This work offered a feasible method to propel the practical application and enriched the sensing mechanisms of BP-based humidity sensors.

Toward Precise n-Type Doping Control in MOVPE-Grown β-Ga2O3 Thin Films by Deep-Learning Approach

In this work, we train a hybrid deep-learning model (fDNN, Forest Deep Neural Network) to predict the doping level measured from the Hall Effect measurement at room temperature and to investigate the doping behavior of Si dopant in both (100) and (010) β-Ga2O3 thin film grown by the metalorganic vapor phase epitaxy (MOVPE). The model reveals that a hidden parameter, the Si supplied per nm (mol/nm), has a dominant influence on the doping process compared with other process parameters. An empirical relation is concluded from this model to estimate the doping level of the grown film with the Si supplied per nm (mol/nm) as the primary variable for both (100) and (010) β-Ga2O3 thin film. The outcome of the work indicates the similarity between the doping behavior of (100) and (010) β-Ga2O3 thin film via MOVPE and the generality of the results to different deposition systems.

WORKING CONDITIONS: WHEN THE RACE FOR PERFORMANCE TURNS SELF-MEDICATION INTO DOPING BEHAVIOR

"The objective of this research was to better understand the link between self-medication and doping behaviors at work (Hautefeuille,2008). More precisely, we wanted to explore how individuals at work practiced self-medication (Fainzang,2012) and how contextual and individual factors could influence their consumption behaviors at workplace. We know that doping behavior could emerge when there is an objective to be achieved or an obstacle faced by the individual (Laure, 2000). To verify this assumption, we have tried to answer this question: “how self-medication could be diverted to doping purposes?”. To study this more closely, we built a methodology based on two tools. First, 17 interviews with workers were done to identify and evaluate the elements and mechanisms derived from working conditions and consumption behaviors, which may explain the consumption behavior at work and, moreover, the doping. Our results allowed us to see that the self-diagnosis phase play an important role in the consumption behavior of individuals. These initial results helped us to create an online questionnaire to which 219 participants responded. For this second tool, we applied a network analysis, using JASP 10.02 software to help us to visualize and understand the link between self-medication and doping behavior. The results of our research indicated that contextual and individual factors had an impact on the psychological state of individuals at work, leading them to develop consumption at work. We have also seen that the practice of self-medication also contributes to the establishment of consumption behavior at work."