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With the rapid development of network technology, college Chinese teaching needs to be reformed as so to adapt to the network environment. This paper puts forward a new strategy of college Chinese teaching based on SNS (social network services) network platform, constructs the model of college Chinese teaching resource allocation, and designs the college Chinese teaching network teaching platform using SNS network method. The routing nodes of SNS network platform are optimized, and the improved PSO (particle swarm optimization) is used to optimize the location of SNS network platform nodes. Based on the node distribution model of PSO, the node overlay connectivity graph of the new SNS network platform of college Chinese teaching is reconstructed to realize the network coverage optimization. The experimental results show that the proposed SNS network platform has better performance of resource scheduling and network connectivity. [ABSTRACT FROM AUTHOR]

The structural characteristics and device performance of strain-compensated InAs/GaAsSb quantum dot solar cells (QDSCs) with different GaP coverages have been studied. The in-plane (out-of-plane) compressive strain of the QD stacks is reduced from -1.24 (+1.06) to -0.39 (+0.33)% by increasing the GaP coverage from 0 to 4 ML. This strain compensation decreases strain-induced dislocation density and hence enhances the overall crystal quality of the QDSCs. The external quantum efficiency spectra reveal that the increase in the GaP coverage increases the photocurrent from wavelengths shorter than GaAs bandedge of 880 nm, while it decreases the photocurrent from near infrared wavelengths beyond the bandedge. The conversion efficiency of the QDSCs is significantly improved from 7.22 to 9.67% as the GaP coverage is increased from 0 to 4 ML. [ABSTRACT FROM AUTHOR]

We have studied the material and photovoltaic characteristics of InAs/GaAsSb sub-monolayer quantum dot solar cells (QDSCs) with different Sb contents of 0%, 5%, 15%, and 20%. All QDSCs exhibit an extended external quantum efficiency (EQE) response in the wavelength range of 960-1000 nm that corresponds to sub-bandgap photon absorption. As Sb content increases from 5% to 20%, the cutoff wavelength in the EQE extends towards longer wavelength whilst the EQE in the wavelength region of 300-880 nm is lowered due to increased defect density. Compared to the QDSC (Sb 0%), an Sb incorporation of 5% enhances the short-circuit current density from 20.65 to 22.15 mA/cm2 induced by Sb surfactant effect. Since the open-circuit voltage and fill factor of the QDSC (Sb 5%) are comparable to those of the QDSC (Sb 0%), an enhancement in solar cell efficiency (10.5%) of the QDSC (Sb 5%) is observed. Further increasing Sb content to 15% and 20% results in the degradation of solar cell performance due to increased nonradiative recombination and large valence band offset in a type-II band line-up. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]