An Emphasis of Electron Energy Calculation in Quantum Wells

We investigate various methods for the calculation of the electron energy in semiconductor quantum wellsand focus on a matrix algorithm method. The results show better fitness of the factor -h/2 / z 1/m* (z) / z than that ofh2/2 1/m*(z) 2/ z2in the first part of the Schrodinger equation. The effect of nonparabolicity in the conduction band isalso discussed.

Microstructural and Electrical Properties of ZrO2 Thin Films prepared on Silicon on Insulator with Thin Top silicon

Amorphous zirconia thin films were deposited directly on silicon-on-insulator(SOI) substrates with this top silicon by ultra-high vacuum electron beam evaporation.Spearding resistance profile and scanning transmission-electron microscopy(TEM) were used to detect the interface quality and microstructure,revealing that the interface between the zirconium oxide films and top silicon was abrupt and clear.The films kept to be amorphous up to the rapid thermal temperature of 700℃for 300s，but arriving at 700℃an unknown interfacial product appeared,which was probably ZrSixOy.High frequency cacacitance-voltage(C-V) characteristics at 1MHz performed on metal-oxide-SOI structure revealed that this interfacial product exhibited good electrical properties of zirconia thin films.When the annealing temperature increased from 600℃to 700℃,flat voltage VFB changed from -2.451to-1.741eV,showing the improvement in the quality of the films,The cumulative region capacitance decreased from 3.058×10^-11 F to 3.012×10^-11F,indicating increasing equivalent oxide thickness,which is in agreement with the result of high-resolution cross-sectional TEM>

Solving Quantum—Nonautonomous System with Non—Hermitian Hanmiltonians by Algebraic Method

A convenient method to exactly solve the quantum-nonautonomous systems with non-Hermitian Hamiltonians is proposed.It is shown that a nonadiabatic complete biorthonormal set can be easily obtained by the gauge transformation method in which the algebraic structure of systems has been used.The nonuitary evolution operator is also found by choosing a special gauge function.All auxiliry parameters introduced in the present approach are only determined by some algebraic equations.The dynamics of two quantum-nonautonomous systems ruled by non-Hermitian Hamiltonians,including a two-photon ionization process involving two-state only and a mesoscopic RLC circuit with a source,are treated as the demonstration of our general approach.

Numerical Analysis of Multilayer Waveguides Using Effective Refractive Index Method

With the help of the effective refractive index method we have numerically analyzed a multilayer planar waveguide structure and calculated the propagation constants, confinement factors, and transverse electric (TE) modes. A five-layer waveguide model has been provided to analyze the electro-magne tic wave propagation process. The analysis method has been applied to the 980 nm laser with active layer of GaInAs/GaInAsP strained quantum wells, GaInAsP confinement layers and GaInP cap layers. By changing the thickness of confinement layers, we obtained confinement factor as high as 95% with higher TE modes TE1 and TE2. The results are in good agreement with the experiment by A. Al-Muhanna et al. and give the new idea to enhance output power of semiconductor lasers. The analysis method can also be extended to any other slab multilayer waveguide structures, and the results are useful to the fabrication of optic-electronic devices.

Transient Intersubband Optical Absorption in Double Quantum Well Structure

The microscopic equations of motion including many-body effects are derived to study the intersubband polarization in the double quantum well structure induced by an ultrafast pumping infrared light. Based on the selfconsistent field theory, the transient probe absorption coefficient is calculated. These calculations are beyond the previous steady-state assumption. Transient probe absorption spectra are calculated under different pumping intensity and various pump probe delay.