Electronic Circuits - Part1: Semiconductors

Classify solid materials as conductors, insulators, or semiconductors, and examine crystalline, polycrystalline, and amorphous structures, including crystal lattices, grain boundaries, and common structures like cubic and diamond.

Explain the simple cubic structure by examining the unit cell with corner atoms, totaling one atom per cell, and derive the atomic packing factor.

Explore how MATLAB serves as a numeric computation tool for engineering and scientific calculations, and learn to calculate and simplify algebraic expressions using the command window, interface, and workspace.

Learn MATLAB operator precedence and parens by deriving the simple cubic atomic packing fraction: use syms r, include pi, compute num and den, then fraction.

Explore the body centered cubic structure, where a unit cell holds corner atoms and a central atom; derive a = 4r/√3 and compute the packing fraction √3 π/8 with MATLAB.

Explain the face-centered cubic unit cell with four atoms and derive the lattice parameter a = 2 sqrt(2) r, yielding the packing fraction pi/(3 sqrt(2)) via MATLAB.

Explore the diamond lattice as a face-centered cubic structure with an eight-atom unit cell and compute x, r, and the atomic packing factor using MATLAB.

Examine atomic packing factors in crystal structures, noting 0.52 simple cubic, 0.68 bcc, 0.74 fcc, 0.34 diamond, and unit-cell atom counts (1, 2, 4, 8) for crystalline vs polycrystalline materials.

Explore atom structure, including electrons, protons, and neutrons. See how nucleus and shells K, L, M, N with sub-orbits s, p, d, f determine Z and the outermost shell's group.

Explore the periodic table's layout, atomic number, and valence electrons across periods and groups, distinguishing metals, semiconductors, non-metals, and noble gases to identify element characteristics.

Atoms lose or gain electrons to fill their outermost valence shell and reach noble gas configurations, forming positive ions (like sodium) or negative ions (like chloride).

Examine the three primary solid bonds—ionic, covalent, and metallic—and how electron transfer, shared electrons in silicon, and free electrons in metals shape stability, structure, and conduction.

Explore how discrete energy levels form continuous energy bands in solids, define valence and conduction bands, and show how gap energy and temperature affect semiconductor conductivity.

Generate electron-hole pairs in semiconductors with thermal energy; generation rises with temperature. Recombine carriers to release energy proportional to electron-hole densities, emitting light that varies with material and defines lifetime.

Achieve ultra-pure intrinsic semiconductors with negligible conductivity at room temperature. Doping creates extrinsic semiconductors—n-type and p-type—with donor and acceptor impurities, producing free electrons and holes, and affecting their mobility.

Adding group 5 impurities to a pure semiconductor forms an n-type extrinsic semiconductor. Donor levels near the conduction band provide free electrons, which become majority carriers, reducing holes.

Introduce p-type semiconductors by adding group 3 impurities such as boron, gallium, indium, or aluminum, creating acceptor levels and holes that dominate current flow, which makes holes the majority carriers.

Explore how energy levels in solids form bands, define the Fermi level, and use the Fermi-Dirac distribution to connect intrinsic and doped semiconductors with electron and hole concentrations.

Plot the fermi-function f(E) at 300 K using the fermi-dirac distribution with Ef = 1 eV in MATLAB, emphasizing vectorized operations and energy points.

Explore mass-action law in semiconductors, showing how n p = ni^2 remains constant under doping, and derive ni = B T^1.5 e^(-Eg/2kT) to reveal temperature-driven intrinsic carrier concentration in silicon.

Explore how n-type and p-type semiconductors form through donor and acceptor impurities, and how electrical neutrality and mass-action law determine electron and hole concentrations.

Demonstrates solving a semiconductor doping problem with the mass-action law (n p = n_i^2) and electrical neutrality in MATLAB, defining symbolic n and p, selecting solutions, using vpa for precision.

Explain drift and diffusion in semiconductors under electric fields, compare electron and hole mobility, and show how drift velocity shapes current density and conductivity.

Explore how pure germanium's conductivity and resistivity at 300 K depend on donor and acceptor impurities, intrinsic electron and hole concentrations, mass-action law, and mobility values.

Explore diffusion current in semiconductors: electrons and holes move from high to low concentration, with diffusion constants Dn or Dp, linked to mobility by Einstein’s VT ≈ 26 mV.

Explore drift and diffusion currents in n-type silicon, calculating current under a 1 V bias across a 2 μm bar using carrier concentrations, electric field, and intrinsic concentration.

Form a pn junction by joining p-type and n-type semiconductors, and explore diffusion and recombination, depletion region, space-charge region, and the built-in voltage via Poisson's equation.

Derive xn and xp from charge equality and voltage continuity, and relate the built-in voltage to doping and temperature. Show how drift and diffusion currents balance in equilibrium.

Adjust donor concentration to 10^16 cm^-3 and add acceptors to reach 0.8 V in pn junction; compute xn, xp, and W with MATLAB, xn ≈0.319 μm and xp ≈0.006 μm.

Explore how a pn junction behaves under external voltage by balancing drift current and diffusion current, and how forward and reverse bias affect depletion width and breakdown.

Derive diode saturation current and junction capacitance from forward and reverse bias, using diffusion of electrons and holes, mass-action law, diffusion lengths Ln and Lp, and the grading coefficient m.

Finish this semiconductors part with a basic understanding of semiconductor materials, and connect via YouTube, LinkedIn, and Twitter for updates, previews, and discounts via QR codes.