Strain-Induced Enhancement of Electroluminescence from Highly Strained Germanium Light-Emitting Diodes

Abstract

The full exploration of Si-based photonic integrated circuits is limited by the lack of an efficient light source that is compatible with the complementary metal− oxide−semiconductor process. Highly strained germanium (Ge) is a promising solution, as its band structure can be fundamentally altered by introducing tensile strain. However, the main challenge lies in the incorporation of an electrical structure while maintaining high strain with uniform distribution in the active region. Here we present highly strained Ge LEDs driven by lateral p−i−n junctions and report the strain-induced enhancement of electroluminescence (EL) from Ge. Raman characterization shows that 1.76% strain along the ⟨100⟩ direction with relatively uniform strain distribution is achieved. The observed strain-induced red-shifts of EL spectra agree well with the theoretical prediction, revealing that the direct band gap of Ge can be tuned in the range of 0.785 eV (1580 nm) to 0.658 eV (1885 nm). This work offers a pathway toward a strained Ge laser with low threshold current, as well as opens possibilities for new types of optoelectronics devices based on strain engineering.

Demonstration of biaxially tensile-strained Ge/SiGe multiple quantum well (MQW) electroabsorption modulators with low polarization dependence

“…The gap between the cutter and the bottom tray is set to be 150 μm so that the chip does not break after dicing. The protecting layer can avoid electrochemical corrosion during the wet etching process [29]. The TMAH solution eats off the Si material through the microbridge window and forms suspended microbridge structure as the solution has a high selection ratio for Si material [30][31][32].…”

High-Sensitivity and Mechanically Compliant Flexible Ge Photodetectors with a Vertical p–i–n Configuration

“…Germanium (Ge) has been one of the most attractive candidates for near-infrared (NIR) applications because of its high absorption coefficient, high mobility, and inherent compatibility with complementary metal oxide semiconductor technology. − In addition, the indirect band gap structure of Ge can be transited to direct by tensile strain, leading to enhanced optoelectronic performance . For example, Kim et al demonstrated flexible NIR Ge PDs based on a metal–semiconductor–metal (MSM) configuration .…”

PIC-integrable, uniformly tensile-strained Ge-on-insulator photodiodes enabled by recessed SiNx stressor

“…However, this poses challenges of electrical interconnections between Si CMOS circuits and the strained materials. The limited number of reports of opto-electronic devices on these strained mate stage for PIC in large devic the other hand with a compr there have a engineering [ remains challe In this wo structure to b erials [13][14][15] a integration. A ce footprint (d , abandoning romised magni also been stu 18,19].…”