Data are presented on the influence of p-type modulation doping on the gain characteristics of 1.3 μm InAs quantum dot lasers. The improvement in optical gain leads to very high characteristic temperatures for the lasing threshold that reach 161 K in the temperature range between 0 and 80 °C. 1.3 μm ground state lasing is obtained up to a temperature of 167 °C.

1.3 μm InAs quantum dot laser with To=161 K from 0 to 80 °C

The influence of p-type modulation doping on self-organized quantum-dot lasers is studied using a quasiequilibrium model that includes the multi-discrete energy levels and the energy levels of the wetting layer. Calculations are presented showing that laser performance can be greatly enhanced through p-doping and that, in contrast to planar quantum-well lasers, the p-doping requirements are moderate. Optimized cavity lengths are found, and the threshold temperature and modulation characteristics are determined for these cavity lengths. The model shows that close energy spacing of the discrete hole levels can severely limit the modulation response, as suggested previously, and that this effect is countered through creation of an excess hole concentration using p-type doping. Good agreement is obtained with the modulation response reported in recent experiments for undoped quantum-dot active regions. The calculations suggest that bandwidths greater than 30 GHz can be obtained with sufficient p-doping. A reduction in the inhomogeneous broadening might increase the laser speed to over 60 GHz.

Modulation characteristics of quantum-dot lasers: the influence of p-type doping and the electronic density of states on obtaining high speed

The modulation response of quantum dot (QD) lasers is analyzed using a quasi-equilibrium approach. The model suggests that present QD lasers are limited due to hole levels that are closely spaced in energy, as well as inhomogeneous broadening. Significant improvements are predicted through p-type modulation doping. The results are consistent with present QD lasers being limited in their modulation response by their differential gain as opposed to carrier capture.

The role of p-type doping and the density of states on the modulation response of quantum dot lasers

The unique optical properties of quantum dot semiconductors have brought about significant new capabilities in light-emitting devices fabricated from these materials. In particular, the performance of laser diodes based on epitaxial quantum dots grown on a GaAs substrate has been the focus of intense study for about 20 years. The advances for such lasers emitting at wavelengths longer than 1.2 μm are reviewed here. Four vital aspects are discussed, including the record-low-threshold currents and the impressive temperature stability these lasers have achieved, the extreme range of linewidth enhancement factors possible in these devices, the ultralow linewidth–power product and insensitivity to optical feedback of quantum dot distributed feedback lasers, and, finally, the progress made to date in achieving higher modulation bandwidths in directly modulated and injection-locked quantum dot lasers.

GaAs-Based Quantum Dot Lasers

Abstract Engineering an efficient semiconductor to sustainably produce green hydrogen via solar-driven water splitting is one of the cutting-edge strategies for carbon-neutral energy ecosystem. Herein, a superhydrophilic green hollow ZnIn 2 S 4 (gZIS) was fabricated to realize unassisted photocatalytic overall water splitting. The hollow hierarchical framework benefits exposure of intrinsically active facets and activates inert basal planes. The superhydrophilic nature of gZIS promotes intense surface water molecule interactions. The presence of vacancies within gZIS facilitates photon energy utilization and charge transfer. Systematic theoretical computations signify the defect-induced charge redistribution of gZIS enhancing water activation and reducing surface kinetic barriers. Ultimately, the gZIS could drive photocatalytic pure water splitting by retaining close-to-unity stability for a full daytime reaction with performance comparable to other complex sulfide-based materials. This work reports a self-activated, single-component cocatalyst-free gZIS with great exploration value, potentially providing a state-of-the-art design and innovative aperture for efficient solar-driven hydrogen production to achieve carbon-neutrality. 

Self-activated superhydrophilic green ZnIn2S4 realizing solar-driven overall water splitting: close-to-unity stability for a full daytime

Bismuth-rich Bi12O17Cl2 nanorods engineered with oxygen vacancy defects for enhanced photocatalytic nitrogen fixation

Self-assembled In/sub 05/Ga/sub 05/As quantum-dot lasers with different doping schemes in the active region are investigated Their lasing wavelength, characteristic temperature, quantum efficiency, and internal loss are characterized and correlated with the size, uniformity, and density of the quantum dots as revealed by atomic force microscopy Continuous-wave operation of Be-doped quantum-dot lasers has been achieved Undoped In/sub 05/Ga/sub 05/As quantum-dot lasers with a characteristic temperature as high as 125 K above room temperature have also been demonstrated

Self-assembled In/sub 0.5/Ga/sub 0.5/As quantum-dot lasers with doped active region

Perovskite Paradigm Shift: A Green Revolution with Lead-Free Alternatives in Photocatalytic CO2 Reduction

Cyano Group Modified Graphitic Carbon Nitride with K Intercalation for Sustainable Photodegradation of Pharmaceutical Waste

Recently, extensive studies on low-dimensional semiconductor heterostructures, including quantum dots and quantum wires, have been carried out for device applications and fundamental researches.[l-3] In this work, we have investigated the lasing characteristics of self-assembled In0.5Ga0.5As quantum dot lasers with doped or undoped quantum dot active region.

Self-assembled In0.5Ga0.5As quantum-dot lasers with doped active region

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Jia-Ming Lee

Author Tools

Chat about Author