JEE Main & Advanced Physics Semiconducting Devices Question Bank Semiconductors

  • question_answer
    A Ge specimen is doped with Al. The concentration of acceptor atoms is ~1021 atoms/m3. Given that the intrinsic concentration of electron hole pairs is \[\tilde{\ }{{10}^{19}}/{{m}^{3}}\], the concentration of electrons in the specimen is                    [AIIMS 2004]

    A)            \[{{10}^{17}}/{{m}^{3}}\]

    B)            \[{{10}^{15}}/{{m}^{3}}\]

    C)            \[{{10}^{4}}/{{m}^{3}}\]  

    D)            \[{{10}^{2}}/{{m}^{3}}\]

    Correct Answer: A

    Solution :

               \[n_{i}^{2}={{n}_{h}}{{n}_{e}}\]Þ  \[{{({{10}^{19}})}^{2}}={{10}^{21}}\times {{n}_{e}}\] Þ \[{{n}_{e}}={{10}^{17}}/{{m}^{3}}.\]


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