Semiconductor photo devices utilize quantum effects on junctions, energies received by electrons that allow electrons to move from the valence tire to the conduction tire under reverse bias conditions.<\/span> Semiconductor materials such as Germanium (Ge) and Silicon (Si) have 4 valence electrons, each electron in an atom is bonded so that the valence electron is even 8 for each atom, which is why the silicon crystals have low electrical conductivity, by the atomic atoms that surround it.<\/span><\/p>\n To form a P-type semiconductor on the material is inserted impurities of class III elements, so that the material becomes more positively charged, due to electron vacuum in the crystal structure.<\/span> When a N-type semiconductor is illuminated by light, the electrons that are not attached to the crystal structure will easily escape.<\/span> Then when the semiconductor is connected type P and type N and then irradiated light, then there will be a voltage difference between the two materials.<\/span><\/p>\n Potential differences in silicone materials generally range from 0.6 volts to 0.8 volts.<\/span> Some of the characteristics of photo diodes that need to be known include: Linear dependent currents on the intensity of light.<\/span> Frequency response depends on the material (Si 900nm, GaAs 1500nm, Ge 2000nm).<\/span> Used as a current source Junction capacitance decreases according to the reverse bias voltage Junction capacitance determines the frequency response of the current obtained.<\/span><\/p>\n The photo diode sensor is a light-sensitive diode, the photodiode sensor will experience a change of resistance when receiving the light intensity and will forward the electric current as the diode in general.<\/span> Photodioda sensor is one type of light sensitive sensor (photodetector).<\/span> Another type of light sensitivity sensor that is often used is phototransistor.<\/span> Photodiode will flow the current forming a linear function to the received light intensity.<\/span> This current is generally regular against power density (Dp).<\/span> The comparison between output current and power density is called current responsitivity.<\/span> The current in question is the leakage current when the photodioda is irradiated and in a downturned state.<\/span> Picture the symbol and the original form<\/span> The frequency response of the photodiode sensor is not broad.<\/span> From that range of responses, the photodiode sensor has the best response to infrared light, precisely at light with a wavelength of about 0.9 \u03bcm.<\/span> The photodiode sensor response curve is shown in the following figure.<\/span><\/p>\n Photodioda Frequency Response Curve<\/b><\/span>
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