Light-triggered two-dimensional lateral homogeneous p-n diodes for opto-electrical interconnection circuits

The realization of light-triggered devices where light is used as external stimulus to control the device performances is a long-standing goal in modern opto-electrical interconnection circuits.In this work,it reveals that light illumination can induce the formation of p-n junctions along two-dimensional conduction channels.The results indicate that the dominant charge carrier type and density in black phosphorus(BP)conduction channel can be effectively modulated by the underlying cadmium sulfide(CdS)photogate layer under light illumination.This enables flexible switching of the working state between BP resistor and BP p-n diode in the designed semi-photo-gate transistor(SPGT)devices when switching the light on and off(ultra-low threshold light power).Simultaneously,the achieved BP p-n junctions also exhibit ultra-high photoresponsivity and evident photovoltaic properties.That is to say,light can be employed as external stimulus to define the BP p-n junctions,and in turn the p-n junctions will further convert the light into electrical power,showing all-in-one opto-electrical interconnection properties.Moreover,the SPGT device architecture is also applicable for construction of other ambipolar semiconductor-based(WSe2-and MoTe2-based)p-n diodes.Such universal all-in-one light-triggered lateral homogeneous pn junctions with ultra-low energy consumption should open a new pathway toward novel optoelectronic devices and deliver various new applications.

Synthesis and opto-electrical properties of Cu2NiSnS4 nanoparticles using a facile solid-phase process at low temperature

Cu_2NiSnS_4 nanoparticles were prepared for the first time using a facile solid-phase process at a temperature of 180 °C. The crystalline structure, morphology and optical properties of the Cu_2NiSnS_4 nanoparticles were characterized by means of X-ray diffraction(XRD), field emission scanning electron microscopy(FESEM), transmission electron microscope(TEM) and ultraviolet-visible(UV-vis) spectrophotometer. The band gap and conversion efficiency of Cu_2NiSnS_4 nanoparticles were studied at various temperature. The results showed that the Cu_2NiSnS_4 nanoparticles exhibited an optimum band gap of 1.58 e V and a conversion efficiency of 0.64% at 180 °C, indicating that it maybe be useful in low-cost thin film solar cells.

Non-volatile programmable homogeneous lateral MoTe2 junction for multi-bit flash memory and high-performance optoelectronics

Flash memories and semiconductor p-n junctions are two elementary but incompatible building blocks of most electronic and optoelectronic devices.The pressing demand to efficiently transfer massive data between memories and logic circuits,as well as for high data storage capability and device integration density,has fueled the rapid growth of technique and material innovations.Two-dimensional(2D)materials are considered as one of the most promising candidates to solve this challenge.However,a key aspect for 2D materials to build functional devices requires effective and accurate control of the carrier polarity,concentration and spatial distribution in the atomically thin structures.Here,a non-volatile opto-electrical doping approach is demonstrated,which enables reversibly writing spatially resolved doping patterns in the MoTe2 conductance channel through a MoTe2/hexagonal boron nitride(h-BN)heterostructure.Based on the doping effect induced by the combination of electrostatic modulation and ultraviolet light illumination,a 3-bit flash memory and various homojunctions on the same MoTe2/BN heterostructure are successfully developed.The flash memory achieved 8 well distinguished memory states with a maximum on/off ratio over 10^4.Each state showed negligible decay during the retention time of 2,400 s.The heterostructure also allowed the formation of p-p,n-n,p-n,and n-p homojunctions and the free transition among these states.The MoTe2 p-n homojunction with a rectification ratio of 10^3 exhibited excellent photodetection and photovoltaic performance.Having the memory device and p-n junction built on the same structure makes it possible to bring memory and computational circuit on the same chip,one step further to realize near-memory computing.