Electro-Optic Modulation Of And Light Source Devices Based On Low-Dimensional Semiconductor

Integrated circuits are the heart of electronic products,reflecting a country’s information technology level and comprehensive technological strength,and have penetrated into all aspects of people’s lives.In the post-Moore era,the rapid development of emerging technologies such as big data,artificial intelligence,and internet of things,has put higher demands on the information processing capabilities of chips.Traditional silicon-based transistors relying on scaling to improve chip integration density and computing power are facing increasingly significant bottlenecks and challenges,such as short-channel effects and off-state energy consumption.Therefore,optoelectronic chips using photons as information carriers have attracted more and more attention due to their high throughput,low power consumption and anti-interference advantages.In the past few years,two-dimensional semiconductor materials-based integrated circuits and discrete devices for optoelectronic interconnections have been successfully fabricated,such as field-effect transistors,photodetectors,electroluminescent devices,memories,and inverters.These new two-dimensional optoelectronic devices with low power consumption,ultra-thin channel,and easy integration are considered to be expected to break through the current technical bottleneck of information transmission.In addition,research progress on single nanostructure-based tunable lasers,which are of great significance to photonic computing chips,is still slow and challenging.Based on the above background,this paper focuses on the research about low-dimensional tunable semiconductor lasers and electroluminescent devices.A variety of high-quality low-dimensional semiconductor materials,including cadmium sulfide（CdS）nanoribbons and monolayer tungsten selenide（ML WSe₂）nanosheets,have been synthesized by chemical vapor deposition and mechanical exfoliation.The modulation mechanism of external bias on photoluminescence of CdS nanoribbons was systematically studied.Based on the modulation effect,a tunable laser based on a single nanostructure was successfully fabricated.At the same time,by constructing p-n junction and MIS（Metal-insulator-semiconductor）junction,an electroluminescent device based on monolayer WSe₂ was successfully realized.The main innovative points and significance obtained are as follows:1.Based on the modulation of electric field on CdS photoluminescence,an electrically controlled laser based on single CdS NR was achieved.The laser exhibits a maximum spectral shift of～10 nm and maximum modulation ratio of 21 d B.Through a series of experimental designs,the contributions of modulation of drift current induced thermal effect and F-K effect on CdS photoluminescence were quantitatively distinguished,laying a foundation for the subsequent design and performance optimization of tunable lasers.This laser has the advantages of reversibility,electrical control and simple structure and is expected to be used in future chip-based wavelength-selectable coherent nanoemitters.2.The p-n junction structure is constructed by using an n-type waveguide and p-type WSe₂,and the waveguide-integrated light-emitting device is realized.The waveguide-integrated light-emitting device exhibits the dual functions of p-n junction luminescence and waveguide coupling.This design simplifies the device structure and is expected to improve the integration level of the chip.The waveguide coupling capability of WSe₂ PL and electroluminescence（EL）with CdS waveguide is successfully demonstrated,which demonstrates its potential for interconnection with other functional optoelectronic units,such as modulators and photodetectors.Most importantly,further interfacing TMDs with well-established III-V and IV semiconductor nanotechnology allows for more flexible control over charge polarity,carrier doping,and micro/nanophotonic integration,which holds great promise for on-chip hybrid PIC technology.（3）AC-driven electroluminescent devices based on different TMD materials were realized.The effect of material polarity on electroluminescence intensity was experimentally demonstrated,and its effect mechanism was explored,which lays a foundation for the further improvement of the device performance.The influence mechanism of voltage inversion on the photoluminescence of different TMD materials is systematically studied,and the high-efficiency modulation characteristics of electric field inversion on the luminescence of materials is expected to realize high-performance electrical modulation devices.