Question: In a semiconductor, <em>J, J<sub>p</sub> </em>and <em>J<sub>n</sub> </em>indicate total diffusion current density hole current density and electron current density respectively, <em>∂n</em>/<em>∂x</em> and <em>∂p</em>/<em>∂x</em> are the electron and hole concentration gradient respectively in <em>x</em>-direction and <em>D<sub>p</sub> </em>and <em>D<sub>n</sub> </em>are the hole and electron diffusion constants respectively. Which one of the following equations is correct? (<em>e </em>denotes charge of electron.)
Answer:
MCQ: In a semiconductor, <em>J, J<sub>p</sub> </em>and <em>J<sub>n</sub> </em>indicate total diffusion current density hole current density and electron current density respectively, <em>∂n</em>/<em>∂x</em> and <em>∂p</em>/<em>∂x</em> are the electron and hole concentration gradient respectively in <em>x</em>-direction and <em>D<sub>p</sub> </em>and <em>D<sub>n</sub> </em>are the hole and electron diffusion constants respectively. Which one of the following equations is correct? (<em>e </em>denotes charge of electron.)
Correct Answer:A. <em>J<sub>n</sub></em> = <em>–eD<sub>n</sub></em>(<em>∂n</em>/<em>∂x</em>) for electrons