5) In a pn junction Si LED (Ks = 11.2), assume that photons are generated uniformly in all directions in a plane perpend

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5 In A Pn Junction Si Led Ks 11 2 Assume That Photons Are Generated Uniformly In All Directions In A Plane Perpend 1 (68.59 KiB) Viewed 11 times

5) In a pn junction Si LED (Ks = 11.2), assume that photons are generated uniformly in all directions in a plane perpendicular to the junction at a distance of 0.5 um from the surface. Assume also that this 0.5 um layer will absorbe 10 % of photons when they reach to the surface. (a) Taking into account total internal reflection and absorption, calculate the fraction of photons that have the potential of being emitted from semiconductor. (b) If Fresnel loss is included, determine the fraction of generated photons that will be emitted from semiconductor into the air. © Repeat part (b) if a coating layer of index of refraction n3 = (nın2)12 is inseted between LED and air. (d) Estimate the external quantum efficiency of this GaAs LED, if the external quantum efficiency of the LED is given by Next = [(2nın2)/(nı + n2)²](1 - cosoc). a: Canon 2 is about