The idea of research is the detection of gases using the transmitter and receiver system for electromagnetic radiation in the IR region using the optical absorption method. As a result of the interaction of the light with the gas molecules can be detect and measure gas pressure adoption absorption method. It was chosen best absorption band between (1.4-1.6) um at the wavelength 1.5 um to build a sensor for accurate measurement of ammonia gas which is characterized by precision, where he was the measuring pressure range (1-6) bar. The importance of the oil industry has been focusing on this kind of scientific research for the detection of ammonia gas.

In this paper, a proposed carbon dioxide Gas Sensing System of high precision, rapid reaction, compact size and low power consumption rate is presented based on the non-dispersive infrared (NDIR) measurement. This system used to determine CO2 gas concentration in air; it consists of the single broadband light source, U-shape tube optical path cavity as gas cell, thermopile detector, and microcontroller circuit. This study investigates the efficiency of the U-tube optical path cavity at CO2 gas concentrations ranging from (0-5000) ppm. The obtained results show that it has the better thermal response compare to the linear tube and exhibits high sensitivity by change the transmitted light intensity into analog voltage. The proposed system design can be used as an environmental monitoring sensor.

The enhancement of the solar cell efficiency field has been achieved in many methods due to the different factors and conditions that led to loss the solar energy. This work deals with the increasing of the efficiency of solar cell that made of single crystalline silicon. This increment achieved by the reduction of biggest type of losses of the conversion efficiency named reflection. by using two methods first; forming grooves on the surface using pulse Nd:YAG laser with max energy 1J and pulse width 10ns, using the fast and accurate movement of the 3D optical galvo mirror scanning system to form the grooves, the second method was by deposition nanomaterials as Silver (Ag) and Cadmium telluride (CdTe) to constitute an antireflection layer for the incident solar spectrum. The effect of antireflection layer material type and the effect of incident light angle on the reflection had been studied in this work. The reflectance had been measured by a system designed and built to give the reflection for angles ranged 0 – 180 degree controlled by Microcontroller. The result inducate that increase in conversion efficiency was 28.3% for Ag/Si, and 32.9% for CdTe/Si than the original efficiency of Si solar cell.

In this work, two forms of nanocrystalline, were used (as-prepared macroPorous silicon and silicon nanoparticle) to synthesize hybrid structures for photodetectors applications. The fabrication pathway was carried out through two 2-steps processes. The 1-step was formation of as-prepared silicon nanoparticle (SiNPs), while and the 2-step was creation of low spam of macroPSi size substrate via electrochemical etching process in HF solutions. Specific features of SiNPs and low spam of macroPSi size substrate were explored using scanning electron microscopy SEM, energy-dispersive x-ray (EDX), Atomic Force Microscope (AFM), and photoluminescence (PL) spectroscopy respectively. Dark and photo current characteristics and spectral responsively of photodetectors were investigated for the macPSi layer and the hybrid structure. The performance of the hybrid configuration shows an improvement in the sensitivity of about 0.75 A/W with appearance of new additional peak at 450nm as compared with the PSi photodetector of about 0.93 A/W. The achieved improvement is related with the appearance of double Heterojunction device between PSi/si and SiNPs/PSi. Also this improvement may be related with the reduction of the reflectd light from the hybrid structure due to the multiple reflection between SiNPs/PSi. The quantum efficiency η of the photodetector in the spectral range 450-700 nm was found to be 65%.

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