The impact of strained layers on current and emerging semiconductor laser systems

Abstract

In this paper, we discuss how the deliberate and controlled introduction of strain can be used to improve the performance of semiconductor lasers. We show how strain-induced modifications of the electronic band structure give rise to significant changes in the valence band of III-V semiconductors which have been used to produce devices with lower threshold currents and higher efficiencies. We furthermore illustrate how the strain limit of semiconductor layers can be overcome by using strain compensation techniques and how this is being widely adopted in lasers based on a number of emerging III-V systems, enhancing device efficiency and output power and extending the wavelength of operation. We show how strained layers are also being used to optimize the performance of mid-infrared lasers through band offset control. Finally, we show how strain may be used to facilitate the production of lasers on silicon through controlling the conduction band valley splitting in group IV semiconductors or through the development of novel direct bandgap III-V systems that may be grown lattice matched to silicon. Such systems are expected to be of significant potential for the future convergence of electronic and photonic devices and highlight the ongoing importance of strain engineering in photonic devices.

Effective Passivation of InGaAs Nanowires for Telecommunication Wavelength Optoelectronics

“…It has been reported that In 0.53 Ga 0.47 As with an emission wavelength at 1550 nm at 80 K, [27] is latticed matched to InP, resulting in a strain-free InGaAs/InP interface. [31] Here, the invariance of the emission peaks after passivation (Figure 3a,b) indicates a negligible strain at the InGaAs/InP interface at these core growth temperatures (600 and 650 °C).…”

“…The observed redshift is attributed to a tensile strain induced by InP passivation layer on InGaAs nanowires. [31] The strain on the In x Ga 1−x As core with a high Ga content (x < 0.5) could be minimized by replacing InP with InGaP as demonstrated by Kim et al [20] Their study improved the core/shell interface quality by growing lattice matched InGaP shells on In x Ga 1−x As nanowires with different Ga contents. [20] Apart from the Ga content and related lattice mismatch, increasing the shell thickness can also increase the strain in the core, resulting in a larger PL shift.…”

Programmed Band Gap Modulation within van der Waals Semiconductor Monolayers by Metalorganic Vapor-Phase Epitaxy

“…In continuous alloy MLs, the variation deviates with a smaller bowing parameter. It may be originated from the local strain build-up within MLs. − The E g size is linearly dependent on the lattice parameters, as typically reported in other ternary semiconductors (Figure k) …”

“…37−39 The E g size is linearly dependent on the lattice parameters, as typically reported in other ternary semiconductors (Figure 2k). 40 In order to gain deeper insights into the atomic structures of WS 2x Se 2(1−x) alloy MLs, we have analyzed a series of the Zcontrast HAADF-STEM images in details, collected from four different spots within the continuous alloy ML in the WS 2 -to-WSe 2 direction, as in Figure 3a−d. The Z-contrast line profiles are sensitive enough to resolve individual Se (S) atoms in the host WS(Se) 2 lattice because of the finite atomic number difference (Z S = 16, Z Se = 34, and Z W = 74).…”

Introduction of misfit dislocations into strained-layer GaAs/InxGa1–xAs/GaAs heterostructures by mechanical bending

“…The long-term reliability of semiconductor lasers is vital to their utility in the telecommunications industry [1], yet strain is often deliberately introduced in the active layer in order to tailor the laser's characteristics and performance [2]. A key factor in that reliability is the stability of the strained layer and, specifically, the propensity to form misfit dislocations at the strained-layer interfaces [3].…”