Multilayer Graphene–GeSn Quantum Well Heterostructure SWIR Light Source

Abstract

The problem of light source always prevents silicon-based photonics from achieving a final integration. Although some optical pump lasers have been reported in recent years, an electrical pumping laser is considered as the ultimate solution. To fabricate a Si-based laser, there are some crucial obstacles that need to be solved such as difficulties in material epitaxy, light absorption by metal electrodes, and compatibility with the existing complementary metal-oxide-semiconductor transistor process. Here, a multilayer graphene and GeSn/Ge quantum well (QW) heterostructure is designed and fabricated as a Si-based light source. Specially designed Ge Sn /Ge QWs are used as active layer, which achieves a photoluminescence (PL) peak at 2050 nm. Graphene, which has a high transmittance for all bands of light, lessens the burden of growing thick cladding layer and perfectly breaks the deadlock of light disappearance in metal contacts. The electroluminescence (EL) spectrum of the device is achieved at a peak of 2100 nm under an injection current density of 100 A cm . Both the PL and EL measurements show the heterostructure has good performance as a short-wave infrared (SWIR) light source. Therefore, the results provides a good alternative for the light source in silicon-based photonics.

Strain Sensors with a High Sensitivity and a Wide Sensing Range Based on a Ti3C2Tx (MXene) Nanoparticle–Nanosheet Hybrid Network

“…Generally, a strain sensor made of a 1D material always exhibits a large working range but a poor sensitivity, since 1D materials with a high aspect ratio can maintain good interconnection while manifesting inconspicuous resistance changes under an extended strain range . Conversely, strain sensors based on 2D materials demonstrate good sensitivity but suffer from low stretchability and stability, which may be related with the low aspect ratio of 2D materials . Recent research has suggested that the strong interaction (i.e., hydrogen bonds or van der Waals forces) between adjacent sheets may play a critical role in narrowing the working range, which obstructs the effective slippage between the sheets so that the 2D materials are inclined to rapidly split into scales and cut off the conductive pathways during the tensile process.…”

The Fabrication of Au@C Core/Shell Nanoparticles by Laser Ablation in Solutions and Their Enhancements to a Gas Sensor

“…In addition, it is also observed that the In 2 O 3 film modified by Au@C nanoparticles has better gas sensing properties than that modified by Au nanoparticles, indicating that the ultrathin carbon layer plays an important role on the gas sensing process. This is due to the unique electronic properties of carbon materials, such as high carrier mobility and the high sensitivity to the changes of resistance [ 38 , 39 , 40 ]. The ultrathin carbon layer can rapidly transform the electric carriers generated from the sensing process, and local p-n heterojunctions are created between carbon layer and In 2 O 3 film, in which the carbon layer plays a role as a p-type semiconductor [ 37 ].…”

Fabrication of High-Quality and Strain-Relaxed GeSn Microdisks by Integrating Selective Epitaxial Growth and Selective Wet Etching Methods

“…However, the low (1%) equilibrium solubility of Sn in Ge [9,10] and the large lattice mismatch (~15%) between Ge and α-Sn introduce enormous challenges for the realization of defect-free GeSn alloy with even a few atomic % of substitutional Sn. The use of non-equilibrium growth techniques such as low-temperature molecular beam epitaxy (MBE) [11][12][13][14][15], chemical vapor deposition (CVD) [16][17][18][19][20], and solid-phase epitaxy [21,22] is in great need.…”