Research on the Force-Sensitive Characteristic of InAs QD Embedded in HEMT

A force-sensitive structure of an InAs Quantum Dot (QD) embedded in a high electron mobility transistor (HEMT) is presented in this paper. The size of an InAs QD is about 30 nm prepared by the S-K growth mode, and the force-sensitive structure is fabricated by molecular beam epitaxy (MBE). The force-sensitivity characteristic of the QD HEMT is studied by the electrical and mechanical properties. The electrical characteristics show that the InAs QD-HEMT has linear, cut-off, and saturation operating states, and produces different output currents under different gate voltages, which shows that the structure is reasonable. Furthermore, the results of the output characteristics under different pressure show that the output voltage of the QD-HEMT decreases with the increase in pressure, which indicates that the InAs QD-HEMT has a vital mechanical–electrical coupling characteristic. The output voltage of the InAs QD-HEMT in the range of 0–100 kPa shows that the sensitivity was 1.09 mV/kPa.

A Review of the Reliability of Integrated IR Laser Diodes for Silicon Photonics

With this review paper we provide an overview of the main degradation mechanisms that limit the long-term reliability of IR semiconductor lasers for silicon photonics applications. The discussion is focused on two types of laser diodes: heterogeneous III–V lasers bonded onto silicon-on-insulator wafers, and InAs quantum-dot lasers epitaxially grown on silicon. A comprehensive analysis of the reliability-oriented literature published to date reveals that state-of-the-art heterogeneous laser sources share with conventional laser diodes their major epitaxy-related degradation processes, such as the generation of non-radiative recombination centers or dopant diffusion, while eliminating cleaved facets and exposed mirrors. The lifetime of InAs quantum dot lasers grown on silicon, whose development represents a fundamental step toward a fully epitaxial integration of future photonic integrated circuits, is strongly limited by the density of extended defects, mainly misfit dislocations, protruding into the active layer of the devices. The concentration of such defects, along with inefficient carrier injection and excessive carrier overflow rates, promote recombination-enhanced degradation mechanisms that reduce the long-term reliability of these sources. The impact of these misfits can be largely eliminated with the inclusion of blocking layers.