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% Document Info
\author{rehman225}
\pdfinfo{
  /Title (semiconductor-physics.pdf)
  /Creator (Cheatography)
  /Author (rehman225)
  /Subject (Semiconductor physics Cheat Sheet)
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\noindent
\begin{multicols}{3}
\begin{tabulary}{5.8cm}{C}
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    {\parbox{\dimexpr\textwidth-2\fboxsep\relax}{\noindent
        \hspace*{-6pt}\includegraphics[width=5.8cm]{/web/www.cheatography.com/public/images/cheatography_logo.pdf}}
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\begin{tabulary}{11cm}{L}
    \vspace{-2pt}\large{\bf{\textcolor{DarkBackground}{\textrm{Semiconductor physics Cheat Sheet}}}} \\
    \normalsize{by \textcolor{DarkBackground}{rehman225} via \textcolor{DarkBackground}{\uline{cheatography.com/152970/cs/32930/}}}
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\noindent
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  \mymulticolumn{2}{p{5.377cm}}{\bf\textcolor{white}{Cheatographer}}  \\
  \vspace{-2pt}rehman225 \\
  \uline{cheatography.com/rehman225} \\
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  \mymulticolumn{1}{p{5.377cm}}{\bf\textcolor{white}{Cheat Sheet}}  \\
   \vspace{-2pt}Published 30th June, 2022.\\
   Updated 30th June, 2022.\\
   Page {\thepage} of \pageref{LastPage}.
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  %\includegraphics[width=48px,height=48px]{dave.jpeg}
  Measure your website readability!\\
  www.readability-score.com
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\begin{multicols*}{2}

\begin{tabularx}{8.4cm}{X}
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Introduction}}  \tn
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\mymulticolumn{1}{x{8.4cm}}{Semiconductors are 4th group of elements in periodic table. \newline % Row Count 2 (+ 2)
valence electrons are 4. \newline % Row Count 3 (+ 1)
ex: Carbon, Silicon, germanium,Tin,lead. \newline % Row Count 4 (+ 1)
Mostly used semiconductor material is Silicon and germanium. \newline % Row Count 6 (+ 2)
semiconductors are negative temperature coefficient as the temperature increases Energy gap of the semiconductor decreases.% Row Count 9 (+ 3)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
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\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Intrinsic Semiconductors}}  \tn
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\mymulticolumn{1}{x{8.4cm}}{An intrinsic semiconductor is a semiconductor in which no other material is intentionally doped (similar to mixing). Example: Si, Ge. \newline % Row Count 3 (+ 3)
Notes:  \newline % Row Count 4 (+ 1)
1. It behaves as an insulator at absolute zero. \newline % Row Count 5 (+ 1)
2. Electrons are excited by thermal energy.  \newline % Row Count 6 (+ 1)
3. They are different from pure semiconductors and may consist of some level of impurities. The conductivity of intrinsic semiconductor is more than that of a pure semiconductor as the impurities provide a few energy levels in the bandgap. \newline % Row Count 11 (+ 5)
Note: \newline % Row Count 12 (+ 1)
Pure semiconductors are  semiconductors that have no impurities. Ideally, no semiconductor is pure in nature.% Row Count 15 (+ 3)
} \tn 
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\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Mass Action Law}}  \tn
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\mymulticolumn{1}{x{8.4cm}}{{\bf{Law of mass action}} \newline % Row Count 1 (+ 1)
The law of mass action states that the product of number of electrons in the conduction band and the number of holes in the valence band is constant at a fixed temperature and is independent of amount of donor and acceptor impurity added. \newline % Row Count 6 (+ 5)
Mathematically it is represented as \newline % Row Count 7 (+ 1)
 {\bf{np = ni\textasciicircum{}2\textasciicircum{} = constant}} \newline % Row Count 8 (+ 1)
               Where ni is the intrinsic carrier concentration \newline % Row Count 10 (+ 2)
                           n is number of electrons in conduction band \newline % Row Count 12 (+ 2)
                           p is number of holes in valence band% Row Count 14 (+ 2)
} \tn 
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Mobility}}  \tn
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\mymulticolumn{1}{x{8.4cm}}{The charge carriers move by the influence of an external electric field. So, due to the application of an electric field charge carriers will get some drift velocity to move in the conductors or the Semiconductors. Electrical mobility of charge carriers is defined as the drift velocity of the carriers per unit applied electric field. \newline % Row Count 7 (+ 7)
Now, what is the electron mobility formula? Let, after applying an external electric field E, the charge carriers get the drift velocity V. Then the formula for the mobility of the charge carriers is, \newline % Row Count 12 (+ 5)
{\bf{μ= V/E}} \newline % Row Count 13 (+ 1)
This is the formula of mobility of charge carriers. This is also the the electron mobility formula.% Row Count 15 (+ 2)
} \tn 
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Einstein Relationship (semiconductor)}}  \tn
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\mymulticolumn{1}{p{8.4cm}}{\vspace{1px}\centerline{\includegraphics[width=5.1cm]{/web/www.cheatography.com/public/uploads/rehman225_1656558068_einsteinrelation.png}}} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
\SetRowColor{LightBackground}
\mymulticolumn{1}{x{8.4cm}}{The equation which relates the mobility µ (of electrons or holes) and the diffusion coefficient (of electrons Dn or holes Dp) is known as Einstein Relationship.}  \tn 
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\begin{tabularx}{8.4cm}{X}
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Classification of Semiconductors}}  \tn
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\mymulticolumn{1}{x{8.4cm}}{There are mainly 2 types of semiconductors \newline % Row Count 1 (+ 1)
1) Intrinsic Semiconductors. \newline % Row Count 2 (+ 1)
2) Extrinsic Semiconductors are of 2 types. \newline % Row Count 3 (+ 1)
     1) P-Type Semiconductor. \newline % Row Count 4 (+ 1)
     2) N-Type Semiconductor. \newline % Row Count 5 (+ 1)
Semiconductor contains electrons and holes.% Row Count 6 (+ 1)
} \tn 
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\begin{tabularx}{8.4cm}{X}
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Extrinsic Semiconductors}}  \tn
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\mymulticolumn{1}{x{8.4cm}}{{\bf{Process of doping}} \newline % Row Count 1 (+ 1)
Doping a semiconductor can be done in many ways including adding impurity to molten semiconductor, heating semiconductor in an atmosphere containing dopant atoms and bombarding semiconductor with the dopant atoms.  \newline % Row Count 6 (+ 5)
{\bf{Types of dopants}} \newline % Row Count 7 (+ 1)
There are two types of dopants that can be added to a semiconductor. This gives rise to the following types of extrinsic semiconductors: \newline % Row Count 10 (+ 3)
1. n-type semiconductor: Pentavalent impurities (Ex: As, P) are added which introduces an extra valence electron which requires lesser energy for conduction. Addition of pentavalent impurity adds a new energy level (called donor levels) near the conduction band in the energy band diagram. \newline % Row Count 16 (+ 6)
2. p-type semiconductor: Trivalent impurities (Ex: B, In) are added which introduces an extra hole which requires lesser energy for conduction. Addition of trivalent impurity adds a new energy level (called acceptor levels) near the valence band in the energy band diagram.% Row Count 22 (+ 6)
} \tn 
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\begin{tabularx}{8.4cm}{X}
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Charge Neutrality}}  \tn
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\mymulticolumn{1}{x{8.4cm}}{A semiconductor is said to be "Electrical neutral" when the total positive charge concentration is equal to total negative charge concentration% Row Count 3 (+ 3)
} \tn 
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\par\addvspace{1.3em}

\begin{tabularx}{8.4cm}{X}
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Types of Materials}}  \tn
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\mymulticolumn{1}{x{8.4cm}}{{\bf{CONDUCTORS}} \newline % Row Count 1 (+ 1)
Contains plenty of free electrons. \newline % Row Count 2 (+ 1)
Energy gap = 0. \newline % Row Count 3 (+ 1)
{\bf{Semi-Conductors}} \newline % Row Count 4 (+ 1)
Contains Valency Electrons = 4. \newline % Row Count 5 (+ 1)
Energy gap = 1eV. \newline % Row Count 6 (+ 1)
{\bf{Insulators}} \newline % Row Count 7 (+ 1)
Tightly bound electrons. \newline % Row Count 8 (+ 1)
Energy gap \textgreater{}6eV.% Row Count 9 (+ 1)
} \tn 
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\begin{tabularx}{8.4cm}{X}
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\mymulticolumn{1}{x{8.4cm}}{\bf\textcolor{white}{Hall Effect}}  \tn
\SetRowColor{white}
\mymulticolumn{1}{x{8.4cm}}{{\bf{Principle of Hall Effect}} \newline % Row Count 1 (+ 1)
The principle of Hall Effect states that when a current-carrying conductor or a semiconductor is introduced to a perpendicular magnetic field, a voltage can be measured at the right angle to the current path. This effect of obtaining a measurable voltage is known as the Hall Effect. \newline % Row Count 7 (+ 6)
The Hall voltage represented as VH is given by the formula: \newline % Row Count 9 (+ 2)
{\bf{V(hall effect) = IB / qnd}} \newline % Row Count 10 (+ 1)
Here, \newline % Row Count 11 (+ 1)
I is the current flowing through the sensor \newline % Row Count 12 (+ 1)
B is the magnetic Field Strength \newline % Row Count 13 (+ 1)
q is the charge \newline % Row Count 14 (+ 1)
n is the number of charge carriers per unit volume \newline % Row Count 16 (+ 2)
d is the thickness of the sensor.% Row Count 17 (+ 1)
} \tn 
\hhline{>{\arrayrulecolor{DarkBackground}}-}
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\par\addvspace{1.3em}


% That's all folks
\end{multicols*}

\end{document}