Novel silicon high sensitive photonic sensor

Light depended resistors (LDR) or photoresistors are semiconductor devices that are changing resistance under illumination. These devices have many applications in industrial controls: item counters, presence and proximity sensors, flame detectors, photometric devices, etc. If the light falling on the device has energy which is greater than the bandgap of the semiconductor, photons absorbed by the semiconductor excite electron-hole pairs which result in lowering the resistance of the semiconductor. Generally, these devices are made of semiconductors such as CdS or CdSe using a thin film technology, since they have traps and misfits in their atomic structure, leading to high dark current and noise. In this work, we describe a novel approach for a novel family of high sensitive light detectors made of single-crystalline silicon. Basic sensor was built in a flat shape providing lateral electrical transport of excited charged carriers. Simple laboratory methods were used to diffuse impurities on both sides of the sensor. The sample shows high sensitivity due to light intensity variation from dark to strong light (∼96,000 lx). A 30 times variation in the sample resistance was obtained.