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प्रश्न
- Assertion (A): Putting the p-type semiconductor slab directly in physical contact with the n-type semiconductor slab cannot form the pn junction.
- Reason (R): The roughness at contact will be much more than inter atomic crystal spacing and continuous flow of charge carriers is not possible.
विकल्प
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
If Assertion is true but Reason is false.
If both Assertion and Reason are false.
उत्तर
If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
Explanation:
A pn junction cannot be formed by physically contacting a p-type semiconductor slab with an n-type semiconductor slab. The roughness upon contact does not match the inter-atomic crystal spacing of about 2-3 Å, resulting in a discontinuity. As a result, a continuous flow of charge carriers is impossible. So both the statement and the reason are correct, and the reason explains the assertion.
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संबंधित प्रश्न
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Extrinsic semiconductor
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Suppose a ‘n’-type wafer is created by doping Si crystal having 5 × 1028 atoms/m3 with 1 ppm concentration of As. On the surface 200 ppm Boron is added to create ‘P’ region in this wafer. Considering n i = 1.5 × 1016 m–3, (i) Calculate the densities of the charge carriers in the n and p regions. (ii) Comment which charge carriers would contribute largely for the reverse saturation current when diode is reverse biased.
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