Define the majority carrier concentration in an n-type Si semiconductor in terms of the conduction band...
1. Define the majority carrier concentration in an n-type Si semiconductor in terms of the conduction band edge energy Ec and the Fermi energy Ep 2 marks Find an expression for Ec - Ep, i.e, the difference between the conduction band edge energy and the Fermi energy in terms of the donor concentration Np. 4 marks Determine the concentration of donor impurity atoms that must be added to silicon that Ec Ef = 0.2 eV So 4 marks
(2) In a semiconductor with an energy gap Eg between the valence and the conduction bands we can take Ef (the Fermi energy) to be halfway between the bands (see figure below): Conduction band Energy gap Eg Valence band Semiconductor a. Show that for a typical semiconductor or insulator at room temperature the Fermi- Dirac factor is approximately equal to exp(-E 2kBT). (Typical Eg for semi-conductors ranges from about 0.5eV to 6eV at T-293K.) b. In heavily doped n-type silicon,...
Silicon at at T-300 K contains acceptor atoms at a concentration of Na-5x10A15 cmA-3. Donor atoms are added forming an n type compensated(counter doped) semiconductor such that the fermi level is 0.215 eV below the conduction band edge 4. a. What concentration of donor atoms were added. b. What were the concentration of holes and electrons before the silicon was counterdoped c. What are the electron and hole concentrations after the silicon was counter doped. Silicon at at T-300 K...
Silicon at at T-300 K contains acceptor atoms at a concentration of Na-5x10A15 cmA-3. Donor atoms are added forming an n type compensated(counter doped) semiconductor such that the fermi level is 0.215 eV below the conduction band edge 4. a. What concentration of donor atoms were added. b. What were the concentration of holes and electrons before the silicon was counterdoped c. What are the electron and hole concentrations after the silicon was counter doped. Silicon at at T-300 K...
Draw the band diagram (the relative positions of conduction band edge EC, valence band edge Ev, Fermi level EF) for the four following cases. Clearly note EC −EF, EF −EV, Ei −EF, EG = EC −EV. Ei is the intrinsic Fermi level. Take NC=NV =1025 m−3, EG=1.1 eV, ni=1.5×1016 m−3, kT=0.026 eV. (Q1.1) p-type, NA=5×1023 m−3. (Q1.2) p-type, NA=5×1021 m−3. (Q1.3) n-type, ND=5×1023 m−3. (Q1.4) n-type, ND=5×1021 m−3. Q2 Draw the band diagram (the relative positions of conduction band edge...
Draw the energy band diagram at equilibrium for the p+ /n/p semiconductor heterostructure (p+ indicates a p-type semiconductor which is heavily doped, i.e., more heavily doped than p). You should indicate Ec (conduction band), Ev (valence band), Ei (intrinsic Fermi level), and Ef (Fermi level) throughout the device structure. show your work (i.e., you should start from the diagram of individual material pieces). State any reason for your drawing.
Problem 1 (25 points) Si at T = 300K contains donor impurity atoms at a density of 5x 10'6cm and acceptor impurity atoms at a density of 2x106 cm-3 . Assume ni 1.5x10'0cm-3, kT-0.026eV a) (5 points) Is the semiconductor n type or p type? b) (10 points) Determine n, and Po c) (10 points) Draw the energy band diagram (Ec, Ev, EFi, Ef) and indicate the position of Ef with respect to Epi Problem 1 (25 points) Si at...
In a semiconductor it can be shown that the product of the electron and hole densities is the square of the intrinsic density, i.e., pm n. Find the equilibrium electron (n) and hole (p) concentrations and the location of the Fermi level (EF) referenced to the conduction band (Ec) or valence band (Ev) in Si at 27°C if the Si contains the following concentrations of shallow dopant atoms: a) 1x1016 cm-3 boron atoms b) 3x1016 cm-3 arsenic atoms and 2.9x1016...
1. a. Find the main error in each of the band diagrams shown below. For all of the band diagrams Ny 1019/cm3, Ne- 1019/cm3, ni = 3 x 108/cm". E,-1.25 eV, T = 300 K. Ef Ef EFi Main error: Main error: Main error: Main error: Consider a semiconductor sample with the following characteristics: EG 1.25 eV, T 300 K, Nd 5 x 101*/cm3, Na 1014/cm3, N.-1019/cm3, N.-1019/cm3, ni-3 × 108/cm3. Assume complete ionization b. Find the equilibrium electron and...
Consider a sample of silicon at 300 K in which the Fermi level is found 0.22 eV above the top of the valence band. a) What type of semiconductor is this sample? b) Sketch the band diagram, labelling Ev, E., E. EF, E. – EF, EF - Ec, and Ea or Ed as applicable. c) What is the carrier concentration of electrons and holes in this sample at thermal equilibrium?