We provide a theoretical analysis of the relative merits of tensile strain and n-type doping as approaches to realizing an efficient low-power germanium laser. Ultimately, tensile strain offers threshold reductions of over 200x, and significant improvements in slope efficiency compared with the recently demonstrated 0.25% strained electrically pumped germanium laser. In contrast, doping offers fundamentally limited benefits, and too much doping is harmful. Moreover, we predict that tensile strain reduces the optimal doping value and that experimentally demonstrated doping has already reached its fundamental limit. We therefore theoretically show large (9 1%) tensile strain to be the most viable path to a practical germanium-on-silicon laser.

This work presents a novel method to introduce a sustainable biaxial tensile strain larger than 1% in a thin Ge membrane using a stressor layer integrated on a Si substrate. Raman spectroscopy confirms 1.13% strain and photoluminescence shows a direct band gap reduction of 100meV with enhanced light emission efficiency. Simulation results predict that a combination of 1.1% strain and heavy n(+) doping reduces the required injected carrier density for population inversion by over a factor of 60. We also present the first highly strained Ge photodetector, showing an excellent responsivity well beyond 1.6um.

Infectious diseases, including COVID-19, are crucial public health issues and may lead to considerable fear among the general public and stigmatization of, and discrimination against, specific populations. This meta-analysis aimed to estimate the pooled prevalence of stigma in infectious disease epidemics. We systematically searched PubMed, PsycINFO, Embase, MEDLINE, Web of Science, and Cochrane databases since inception to June 08, 2021, and reported the prevalence of stigma towards people with infectious diseases including SARS, H1N1, MERS, Zika, Ebola, and COVID-19. A total of 50 eligible articles were included that contributed 51 estimates of prevalence in 92722 participants. The overall pooled prevalence of stigma across all populations was 34% [95% CI: 28−40%], including enacted stigma (36% [95% CI: 28−44%]) and perceived stigma (31% [95% CI: 22−40%]). The prevalence of stigma in patients, community population, and health care workers, was 38% [95% CI: 12− 65%], 36% [95% CI: 28−45%], and 30% [95% CI: 20−40%], respectively. The prevalence of stigma in participants from low- and middle-income countries was 37% [95% CI: 29−45%], which is higher than that from high-income countries (27% [95% CI: 18−36%]) though this difference was not statistically significant. A similar trend of prevalence of stigma was also observed in individuals with lower education (47% [95% CI: 23−71%]) compared to higher education level (33% [95% CI: 23−4%]). These findings indicate that stigma is a significant public health concern, and effective and comprehensive interventions are needed to counteract the damaging effects of the infodemics during infectious disease epidemics, including COVID-19, and reduce infectious disease-related stigma.

Hierarchical nanotube arrays with complex shell structures are attractive for applications in electrode materials for effectively boosted electrochemical performance, but the construction of such delicate architectures with excellent electrochemical performance...