Enhanced carrier collection efficiency of GeSn single quantum well towards all-group-IV photonics applications

Abstract

GeSn-based quantum wells are of great interests for the development of all-group-IV optoelectronic devices such as lasers. Using a GeSn buffer and SiGeSn barrier has been studied with the aim of obtaining a direct bandgap well and increasing the carrier confinement. However, the carrier collection efficiency with such a configuration remains unsatisfactory. In this work, a single quantum well with additional GeSn barrier inserted between the GeSn well and the SiGeSn barrier was grown and characterized. Under relatively low carrier injection, the photoluminescence results show dramatically enhanced emission from the quantum well compared to the reference samples with only SiGeSn barrier, indicating a significantly improved carrier collection efficiency of the well.

Study of all-group-IV SiGeSn mid-IR lasers with dual wavelength emission

“…The lasing behavior will be discussed in the next section. All samples were grown using an industry-standard CVD reactor with low-cost commercially available precursors for Si, Ge, and Sn, respectively 27 . First, a ~ 1 μm thick Ge buffer layer was grown on Si(001) substrate by a two-step growth method, at low and high temperatures, to promote layer-by-layer growth and ensure high material quality 28 .…”

The growth of Ge and direct bandgap Ge1−xSnx on GaAs (001) by molecular beam epitaxy

“…1,2 The tunability of GeSn lends itself to be a great candidate for the next generation of near-and mid-infrared lasers and photodetectors. 1,[3][4][5][6][7][8] However, achieving the growth of good quality GeSn with signicant Sn content is typically challenged by a lattice mismatch between the substrate and GeSn. One possibility is to use a tuneable substrate that allows for a lattice match of different alloy compositions of GeSn.…”

Growth of Germanium Thin Films on Sapphire Using Molecular Beam Epitaxy

“…Given that the silicon semiconductor has been the backbone of our economic and military strength, one might think that the best platform for this photonic system is to integrate the laser light source, active optical elements, and operating microwave electronics all onto a silicon chip. However, while silicon has been more than great for electronics, it has been less so for photonics [2]. For example, despite many efforts by the photonics community over a long period of time, a satisfactory silicon laser has not yet been developed.…”

“…To address this challenge in microwave photonics, we pursued the fabrication of a monolithic integrated group IV GeSn semiconductor laser [10][11][12] on a sapphire substrate. The choice to investigate the sapphire platform was based on several advantages it has over current silicon technology, such as (1) significantly greater immunity to the defects of space radiation [13,14], (2) high index contrast for efficient waveguides [15][16][17], (3) nearly perfect thermal expansion match to Group IV and III-V semiconductors for durability [18], and (4) the flexibility to support the monolithic fabrication of both laser and photonic integrated circuits on one platform, allowing higher function at a reduced cost. Sapphire is already used as an ideal substrate for microwave devices [19,20], and adding optical elements to sapphire is an attractive possibility to realize microwave photonic chips.…”