From 0c1dcfbe0bbf8d87edef4f78bbce911a49ddda0c Mon Sep 17 00:00:00 2001 From: Kostas Vilkelis <kostasvilkelis@gmail.com> Date: Fri, 26 Mar 2021 14:10:17 +0000 Subject: [PATCH] fix math eq bugs --- src/14_doping_and_devices.md | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/src/14_doping_and_devices.md b/src/14_doping_and_devices.md index 6dd479dc..004fe38f 100644 --- a/src/14_doping_and_devices.md +++ b/src/14_doping_and_devices.md @@ -65,9 +65,10 @@ Therefore, the electron's mass is the conduction band's effective mass. Furthermore, the interactions between the electron and proton are screened by the lattice. As a result, we need to introduce the following substitutions: $m_e \to m_e^*$, $\epsilon_0 \to \epsilon\epsilon_0$. We thus estimate the energy of the bound state created by the impurity: -$$E = -\frac{m_e^*}{m_e \varepsilon^2} R_E = -0.01 \text{eV (in Ge)}$$ -$r_B = 4$ nm (vs $r_B = 0.5$ Ã… in H)$. -The electron is very weakly bound to the impurity! At room temperature (0.026 eV), the donor electron is easily thermally excited into the conduction band. +$$E = -\frac{m_e^*}{m_e \varepsilon^2} R_E = -0.01 \text{eV (in Ge)},$$ +with Bohr radius $r_B = 4$ nm (vs $r_B = 0.5$ Ã… in Hydrogen). +The electron is very weakly bound to the impurity! +At room temperature (0.026 eV), the donor electron is easily thermally excited into the conduction band. On the other hand, we can add a group III element to reduce the average number of electrons in the system. Group III elements lacks 1 electron and 1 proton and are therefore known as **acceptors**. @@ -103,7 +104,7 @@ Therefore, we model the density of states of donors/acceptors as a Dirac delta f $$ g_D(E) = N_D \delta(E- E_D), \quad g_A(E) = N_A \delta(E-E_A), $$ -where N_D and N_A are donor and acceptor concentrations respectively. +where $N_D$ and $N_A$ are donor and acceptor concentrations respectively. The binding energies of the donor and acceptor are defined as $E_A$ and $E_D$. How good is this Dirac delta approximation? -- GitLab