Aim We evaluated the feasibility and acceptability of Horyzons, an online social media platform designed to facilitate relationship development among, and introduce therapeutic content to, first‐episode psychosis (FEP) clients. We also evaluated whether participation in the platform was related to reduced loneliness, improved social integration and increased psychological well‐being. Methods Twenty‐six participants diagnosed with a schizophrenia spectrum disorder were provided access to the moderated Horyzons platform for 12 weeks. During the intervention period, participants were encouraged to access therapeutic content and social components embedded within the site. Participants were recruited from three first‐episode coordinated specialty care clinics in North Carolina and assessed at four time points: baseline, mid‐treatment, post‐treatment and 1‐month follow‐up. Results Findings indicated that Horyzons was both feasible and very well tolerated, with a 92.3% retention rate and 79.2% of participants actively engaged in the platform. The most commonly identified personal strengths selected by Horyzons users were creativity (61.5%), curiosity (42.3%) and courage (38.5%). Feedback from participants indicated Horyzons could be improved by the development of a smartphone application, expanding the size of the Horyzons community and facilitating private messages between users. Preliminary results with engaged participants showed the greatest improvements in psychosis‐related symptoms, followed by self‐reported experience of negative emotions, depressive symptoms and loneliness. Conclusions This open trial found that Horyzons is both feasible and acceptable to FEP persons early in the course of illness living in the United States.

Motivated by its potential properties and applications, the energy band alignment of the amorphous-crystalline Ge2Sb2Te5 heterojunction in thermal equilibrium is explored. An analytic model based on the exact solution to Poisson’s equation is constructed to describe the electrostatics of the heterojunction between the amorphous phase and the face-centred cubic crystalline phase of Ge2Sb2Te5. The model captures the physics of accumulation in the crystalline layer, as well as that of depletion and inversion due to the deep defect distributions in the bulk of the amorphous layer. Without introducing fitting parameters, the model approximates the influence of the density of states parameters of each phase on the electric potential distribution across the heterojunction. It is then validated against the exact solution obtained numerically using Solar Cell Capacitance Simulations. Apart from the small inaccuracy in modelling the electric potential distribution in the depletion region, simulation results reveal that the approximations are successful in modelling the electrostatics of the heterojunction.

The transport of holes through a representative isotype amorphous-crystalline Ge2Sb2Te5 heterojunction under forward bias is explored for the first time. An approximate analytic model, based on the exact solution to Poisson’s Equation, the Continuity Equation, and the Transport Equation, is proposed to describe the forward current-voltage characteristic and hole quasi-Fermi level distribution across the heterojunction with a reduced set of material and device parameters. The proposed model incorporates thermionic emission across the heterojunction interface as well as drift and diffusion across the quasi-neutral regions of the heterojunction layers, but neglects drift and diffusion across the space-charge regions of the heterojunction layers, as well as recombination. Solar cell capacitance simulation results demonstrate general agreement between the approximate and exact solutions. Therefore, the approximate model is effective in capturing the physics of thermionic emission-limited transport at low applied bias and drift-diffusion-limited transport through the quasi-neutral region of the amorphous layer at larger applied biases. However, simulation results also show that an extremely narrow subregion of the space-charge region within the amorphous layer, which has been neglected within the proposed model, limits the transport of holes at very low bias and inhibits transport at all other biases. Nevertheless, the proposed model provides improved accuracy across the entire bias range compared to the individual thermionic emission or drift-diffusion models.

Motivated by future data storage requirements, Ge2Sb2Te5 is studied for application in phase-change random access memory. The currently accepted density of states models for the cubic crystalline phase, based on first-principles calculations, are reviewed. An alternative density of states model, which incorporates band tails and an Antimony vacancy multivalent defect, is proposed. Solar Cell Capacitance Simulator results reveal that it is successful in estimating a free hole concentration and Fermi Level position consistent with previous Hall Effect and thermopower measurements respectively. The conduction band tail, which has not previously been incorporated within the density of states model of the crystalline phase, is shown to contribute to this success.