Problem 2.2 Calculate the lattice constant, bandgap, and electron effective mass of the alloy In, Ga1-As...
The bandgap of a GaAs laser is 1.0 eV and the effective mass of the valence band is half of the effective mass of the conduction band. Assuming that the recombination transition is at 0.03 above the band gap calculate the transition wavelength.
Consider a free electron, empty lattice model with effective mass m* in a simple cubic crystal with direct lattice distance a, and reciprocal lattice vectors of length a. Find the energies at the high symmetry points Г, X, M and R and indicate the zone boundary rsion along TX, TR, Г b. Find the expression for the lowest energy band in the XM direction. Sketch the Energy band diagram along RIXM「 c.
The bandgap of a GaAs laser is 1.0 eV and the effective mass of the valence band is half of the effective mass of the conduction band. Assuming that the recombination transition is at 0.03 above the band gap calculate the transition wavelength.
Problem 4. In a simple 1-d tight binding model, the electron energy is given by an expression E--2tcos(ka) where a is the lattice constant and k is the wave vector. What is the electron effective mass at k-0.
A magnesium-lead alloy of mass 9.7 kg consists of a solid α phase that has a composition just slightly below the solubility limit at 300°C (570°F). The magnesium-lead phase diagram is shown in Animated Figure 10.20. (a) What mass of lead is in the alloy? kg (b) If the alloy is heated to 400°C (750°F), how much more lead may be dissolved in the α phase without exceeding the solubility limit of this phase? wt%Pb = (m_Pb + m_add /...
(0)If in GaAs, the Fermi level is 0.30 eV below the conduction band. [10] calculate the thermal equilibrium electron and hole concentration at room temperature. Bandgap of CaAs is 1.42 eV, the effective density of states of the conduction band at 300K is 4.7x10 cm and the effective density of states of the valence band is 7x10¹ cm³.L213(11)Identify and illustrate with required equations and diagrams, how energy and momentum are conserved in band to band transitions in indirect band gap...
Please explain part b in details thx! Question 2 At 300 K, the bandgap of GaP is 2.26 eV and the effective density of states at the conduction and valence band edge are 1.8 x 1019 cm23 and 1.9 x 1019 cm3, respectively. (a) Calculate the intrinsic concentration of GaP at 300K (7 marks) Calculate the GaP effective mass of holes at 300K. (b) (8 marks) (c The GaP sample is now doped with donor concentration of 1021 cm3 with...
Calculate the effective nuclear charge of an electron in a cobalt (Co) atom if it has a screening constant of 20.2. 6)
Gibbs free energy of an alloy (9 marks The stability of a pseudobinary alloy (see lecture week 5) is subject to the minimization of the Gibbs free energy of mixing Let us consider the pseudobinary alloy AB1-C which crystallizes as a zincblende. The solid solution can be considered as formed by the 5 possible tetrahedra with an atom C in the centre and A or B atoms at the corners A4C, A3BC, A2B2C, AiB3C B4C which can be written as...
Consider the free electron energy bands of an fcc crystal lattice in the empty lattice approximation in the reduced zone scheme in which all k’s are in the first Brillouin zone. Plot in the [111] direction the energies of all bands up to 6 times the lowest band energy at the zone boundary at = (2?/a)( 1/2 , 1/2 , 1/2 ). Let this be the unit of energy. This problem shows why band edges need not be necessarily at...