Substantial P-Type Conductivity of AlN Achieved via Beryllium Doping.

Beryllium has long been predicted by first principle theory as the best p-type dopant for GaN and AlN. But experimental validation of these theories has not, until now, borne out the original predictions. A key challenge is the dopant-induced strain leading to Be rejection from substitutional sites in favor of interstitial sites, leading to self-compensation.

Comprehensive Analysis of Metal Modulated Epitaxial GaN.

While metal modulated epitaxy (MME) has been shown useful for hyperdoping, where hole concentrations 40 times higher than other techniques have been demonstrated, and the ability to control phase separation in immiscible III-nitrides, the complexity of the dynamically changing surface conditions during the cyclic growth is poorly understood. While MME is capable of superb crystal quality, performing MME in an improper growth regime can result in defective material. These complications have made the transfer of MME knowledge challenging.

Self-rated health in a population of expatriate workers and partners in Riyadh, Saudi Arabia.

Background: Anthropological theory suggests that expatriate workers progress through a sequence of adaptive stages during their adjustment to a new environment. The psychological and physiological effects of this adaptation process may be reflected in changes in self-rated general health.

Aims: To explore the relationship between self-rated general health, duration of expatriate assignment and two health-related behaviours: physical exercise and cigarette smoking.