Forward and reverse electron transport properties across a CdS/Si multi-interface nanoheterojunction

The electron transport behavior across the interface plays an important role in determining the performance of op- toelectronic devices based on heterojunctions. Here through growing CdS thin film on silicon nanoporous pillar array, an untraditional, nonplanar, and multi-interface CdS/Si nanoheterojunction is prepared. The current density versus voltage curve is measured and an obvious rectification effect is observed. Based on the fitting results and model analyses on the forward and reverse conduction characteristics, the electron transport mechanism under low forward bias, high forward bias, and reverse bias are attributed to the Ohmic regime, space-charge-limited current regime, and modified Poole-Frenkel regime respectively. The forward and reverse electrical behaviors are found to be highly related to the distribution of inter- facial trap states and the existence of localized electric field respectively. These results might be helpful for optimizing the preparing procedures to realize high-performance silicon-based CdS optoelectronic devices.

Influence of Different Al Contents on Microstructure, Tensile and Wear Properties of Zn-based Alloy

The influence of different Al contents on the microstructure, hardness, tensile and wear behavior of Zn-based alloys was investigated in the present study. The test results show that alloy with 27% Al content shows the higher ultimate strength and elongation percent at room and elevated temperatures. It also exhibits the higher wear resistance at all loads in view of the higher tightness of Zn-27Al alloy. Increasing Al content from 33% to 48% results in improvement of ultimate strength and elongation percent at room and elevated temperatures. However, the ultimate strength and elongation percent of the ZA48 alloy are still lower than that of Zn-27Al alloys. The reason can be attributed to the increasing segregation and voids with increasing Al contents.

Capacitive humidity sensing properties of carbon nanotubes grown on silicon nanoporous pillar array

Multi-walled carbon nanotubes (CNTs) were grown on silicon nanoporous pillar array (Si-NPA) by thermal chemical vapor deposition method, and the structural and capacitive humidity sensing properties of CNT/Si-NPA were studied. It was found that with the relative humidity (RH) changing from 11% to 95%, a device re-sponse of ~480% was achieved at the frequency of 50000 Hz, and a linear device response curve could be obtained by adopting longitudinal logarithmic coordinate. The response/recovery times were measured to be ~20 s and ~10 s, respectively, which indicated a rather fast response/recovery rate. The adsorption-desorption dynamic cycle experiments demonstrated the high measurement reproducibility of CNT/Si-NPA sensors. These excellent performances were attributed to the unique surface structure, morphology and chemical inertness of CNT/Si-NPA.

Diode-pumped high-efficiency broadband tunable Tm:YAP laser

A laser diode-pumped high-efficiency widely tunable Tm：YAP laser with excellent comprehensive prop- erties is reported. The output power is stable at a given pump power. Under the absorbed pump power of 12.95 W, the maximum output power at 2,010 nm is 5.16 W, corresponding to a slope efficiency of 45.5%. The generated beam profile is close to the Gaussian TEM00 near the maximum pump power. Furthermore, the laser working wavelength can be continuously tuned through optimization from 1,894 to 2,066 nm, which is the widest tunable range for Tm：YAP lasers to date.