Review on conductivity enhancement in n-ZnO/p-Si heterojunction diodes with the influence of Rare earth ions as donor impurities.

Nanoelectronics is an emerging field of nanotechnology where innumerable nanomaterials are used to fabricate electronic devices like LEDs, Photodiodes, Transistors, FETs, UJTs, SCRs, Laser diodes, etc.  The accomplishment of high-efficiency electronic devices at low cost tends to be the foremost challenging task in the field of nanoelectronics. The p-n heterojunction is a junction of two dissimilar p and n-type crystalline materials with different bandgap energies, work functions and electron affinities.The n-ZnO/p-Si heterojunction device tends to be cost-effective and also potential candidates for integration with microelectronic based photonic and optoelectronic devices. Th electrical properties of n-ZnO/p-Si heterojunction diode can be fine-tuned by the addition of dopants at different concentrations.This article presents a brief overview on the influence of different  rare earth dopants on chargecarrier enhancement and transport mechanism in n-ZnO/p-Si heterojunction diode. This review paper also presents an outline on heterojunction formation theories and applications of n-ZnO/p-Si heterojunction diod

Diurnal and seasonal influence on the indoor radon levels in dwellings of Sharjah Emirate as well its estimation of annual effective dose

Radon, a proven highly carcinogenic gas, has raised serious concerns, necessitating its measurement in residential areas. In the coastal city of Sharjah, United Arab Emirates (UAE), the first indoor radon concentration measurements were conducted. Following the Environmental Protection Agency (EPA) protocol, active radon detectors were employed in the living rooms of houses across the south-east region of the city. Measurements revealed that, the mean values during winter are of (39.6 ± 12.2) Bq/m3 (floor 1) and (35.7 ± 9.8) Bq/m3 (floor 2), while in summer, levels were slightly higher on floor 1 (55.8 ± 10.1) Bq/m3 compared to floor 2 (47.8 ± 12.6) Bq/m3. Ground floor analysis showed mean values of (57.0 ± 12) Bq/m3 in summer and (49.0 ± 16) Bq/m3 in winter. Higher summer levels were linked to climatic conditions and increased time spent indoors. The excess lifetime cancer risk for ground floor radon was estimated as 0.341% over 25 years. Annual dose equivalent was calculated using International Commission on Radiological Protection (ICRP) and United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) models. The calculated results were found to range from 1.7 to 3.0 millisieverts (mSv), which is within permissible limits

Ultra-sensitive and fast optical detection of the spike protein of the SARS-CoV-2 using AgNPs/SiNWs nanohybrid based sensors

International audienceSevere acute respiratory syndrome SARS-CoV-2 virus led to notable challenges amongst researchers in view of development of new and fast detecting techniques. In this regard, surface-enhanced Raman spectroscopy (SERS) technique, providing a fingerprint characteristic for each material, would be an interesting approach. The current study encompasses the fabrication of a SERS sensor to study the SARS-CoV-2 S1 (RBD) spike protein of the SARS-CoV-2 virus family. The SERS sensor consists of a silicon nanowires (SiNWs) substrate decorated with plasmonic silver nanoparticles (AgNPs). Both SiNWs fabrication and AgNPs decoration were achieved by a relatively simple wet chemical processing method. The study deliberately projects the factors that influence the growth of silicon nanowires, uniform decoration of AgNPs onto the SiNWs matrix along with detection of Rhodamine-6G (R6G) to optimize the best conditions for enhanced sensing of the spike protein. Increasing the time period of etching process resulted in enhanced SiNWs’ length from 0.55 to 7.34 µm. Furthermore, the variation of the immersion time in the decoration process of AgNPs onto SiNWs ensued the optimum time period for the enhancement in the sensitivity of detection. Tremendous increase in sensitivity of R6G detection was perceived on SiNWs etched for 2 min (length=0.90 µm), followed by 30s of immersion time for their optimal decoration by AgNPs. These SiNWs/AgNPs SERS-based sensors were able to detect the spike protein at a concentration down to 9.3 × 10−12 M. Strong and dominant peaks at 1280, 1404, 1495, 1541 and 1609 cm−1 were spotted at a fraction of a minute. Moreover, direct, ultra-fast, facile, and affordable optoelectronic SiNWs/AgNPs sensors tuned to function as a biosensor for detecting the spike protein even at a trace level (pico molar concentration). The current findings hold great promise for the utilization of SERS as an innovative approach in the diagnosis domain of infections at very early stages