“carrier concentration”的概念、定义、翻译、参考文献-科学参考

carrier concentration

Electronics and Electrical Engineering

The number of charge carriers in a semiconductor per unit volume, in practice usually quoted as numbers per cubic centimetre. In an intrinsic (i-type) semiconductor the number of holes, p, and of electrons, n, is equal to the intrinsic density, n_i:
$n = p = n_{i}$
where
$n_{i}^{2} = N_{c} N_{v} exp (- \frac{E_{g}}{k T})$
where N_c and N_v are the effective densities of energy states in the conduction and valence bands respectively, E_g is the difference in energy between the conduction and valence bands, k is the Boltzmann constant, and T the thermodynamic temperature.
In an extrinsic semiconductor the electrical neutrality of the sample is preserved and in a sample that contains impurities,
$N_{A}^{-} + n = N_{D}^{+} + p$
where N_A⁻ and N_D⁺ are the numbers of ionized acceptor and donor impurities, respectively. At relatively high temperatures most of the impurity atoms are ionized and it is possible to state that
$n + N_{A} = p + N_{D}$
where N_A and N_D are the total numbers of acceptors and donors. The product np = n_i² is independent of added impurities.
In an n-type semiconductor the number of electrons, n_n, at thermal equilibrium is given by
$n_{n} n = | N_{D} - N_{A} |$
provided N_D > N_A >> n_i
Carrier concentrations in semiconductors
The number of holes, p_n, in an n-type semiconductor is given by
$p_{n} = \frac{n_{i}^{2}}{n_{n}}$
In a p-type semiconductor the situation is reversed:
$p_{p} = | N_{A} - N_{D} |$
provided N_A >; N_D >> n_i
The number of electrons is given by
$n_{p} = \frac{n_{i}^{2}}{p_{p}}$
The carrier concentrations of i-, n-, and p-type semiconductors are shown schematically in the diagram, where E_A and E_D are the locations of the energy levels of the acceptor and donor impurities respectively.

单词	carrier concentration
释义	carrier concentration Electronics and Electrical Engineering The number of charge carriers in a semiconductor per unit volume, in practice usually quoted as numbers per cubic centimetre. In an intrinsic (i-type) semiconductor the number of holes, p, and of electrons, n, is equal to the intrinsic density, n_i: $n = p = n_{i}$ where $n_{i}^{2} = N_{c} N_{v} exp (- \frac{E_{g}}{k T})$ where N_c and N_v are the effective densities of energy states in the conduction and valence bands respectively, E_g is the difference in energy between the conduction and valence bands, k is the Boltzmann constant, and T the thermodynamic temperature. In an extrinsic semiconductor the electrical neutrality of the sample is preserved and in a sample that contains impurities, $N_{A}^{-} + n = N_{D}^{+} + p$ where N_A⁻ and N_D⁺ are the numbers of ionized acceptor and donor impurities, respectively. At relatively high temperatures most of the impurity atoms are ionized and it is possible to state that $n + N_{A} = p + N_{D}$ where N_A and N_D are the total numbers of acceptors and donors. The product np = n_i² is independent of added impurities. In an n-type semiconductor the number of electrons, n_n, at thermal equilibrium is given by $n_{n} n = \| N_{D} - N_{A} \|$ provided N_D > N_A >> n_i Carrier concentrations in semiconductors The number of holes, p_n, in an n-type semiconductor is given by $p_{n} = \frac{n_{i}^{2}}{n_{n}}$ In a p-type semiconductor the situation is reversed: $p_{p} = \| N_{A} - N_{D} \|$ provided N_A >; N_D >> n_i The number of electrons is given by $n_{p} = \frac{n_{i}^{2}}{p_{p}}$ The carrier concentrations of i-, n-, and p-type semiconductors are shown schematically in the diagram, where E_A and E_D are the locations of the energy levels of the acceptor and donor impurities respectively.
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