In the past few decades, numerous high-performance silicon (Si) photonic devices have been demonstrated. Si, as a photonic platform, has received renewed interest in recent years. Efficient Si-based III-V quantum-dot (QDs) lasers have long been a goal for semiconductor scientists because of the incomparable optical properties of III-V compounds. Although the material dissimilarity between III-V material and Si hindered the development of monolithic integrations for over 30 years, considerable breakthroughs happened in the 2000s. In this paper, we review recent progress in the epitaxial growth of various III-V QD lasers on both offcut Si substrate and on-axis Si (001) substrate. In addition, the fundamental challenges in monolithic growth will be explained together with the superior characteristics of QDs.

With continuously growing global data traffic, silicon (Si)-based photonic integrated circuits have emerged as a promising solution for high-performance Intra-/Inter-chip optical communication. However, a lack of a Si-based light source remains to be solved due to the inefficient light-emitting property of Si. To tackle the absence of a native light source, integrating III-V lasers, which provide superior optical and electrical properties, has been extensively investigated. Remarkably, the use of quantum dots as an active medium in III-V lasers has attracted considerable interest because of various advantages, such as tolerance to crystalline defects, temperature insensitivity, low threshold current density and reduced reflection sensitivity. This paper reviews the recent progress of III-V quantum dot lasers monolithically integrated on the Si platform in terms of the different cavity types and sizes and discusses the future scope and application.

Background Percutaneous biliary drainage (PTBD) is a necessary procedure in several benign and malignant conditions. After PTBD removal biliocutaneous fistula is a rare but potential complication. Different embolization agents have been used for transhepatic catheter tract embolization in the past, while there is only little experience using gelatin sponge for this procedure. Purpose To evaluate the feasibility and safety of PTBD tract embolization with gelatin sponge. Material and Methods Between July 2008 and August 2017, 98 patients have been treated with PTBD access embolization using gelatin sponge. PTBD was performed in patients with malignant (67%) or benign (33%) bile duct obstruction. Outcome measures included technical success (complete cessation of bile flow out of the percutaneous access tract), clinical success (intermediate and long-term absence of biliocutaneous fistula, absence of right upper quadrant pain as typical symptom for bile leakage into the peritoneal cavity and absence of hemorrhage out of the catheter tract during follow-up inspections), and the rate of major and minor complications. Results Technical success with effective control of bile flow out of the percutaneous access tract was achieved in 97/98 patients (99.0%). Clinical success attributed to gelatin sponge embolization was documented in 96/98 procedures (98.0%). In one case, slight bleeding out of the percutaneous drainage tract occurred after drainage removal and embolization of the access tract. Bleeding was self-limiting; no blood transfusion or surgical intervention was necessary. Conclusion PTBD tract embolization with gelatin sponge is a feasible and safe method with a low rate of therapeutically relevant complications.

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We discuss our recent progress made in the direct growth of 1.3 µm InAs/GaAs quantum dot (QD) light-emitting sources on Si substrates for Si photonics.