R. Hünlich

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The reconstruction method presented here is based on diffusion approximation for light propagation in turbid media and on a minimization strategy for the output-least-squares problem. A perturbation approach is introduced for the optical properties. Here we can strongly reduce the number of free variables of the inverse problem by exploiting a priori(More)
In this paper we prove a global existence result for pair diffusion models in two dimensions. Such models describe the transport of charged particles in semiconductor heterostructures. The underlying model equations are continuity equations for mobile and immobile species coupled with a nonlinear Poisson equation. The continuity equations for the mobile(More)
This paper demonstrates simulation tools for edge-emitting multi quantum well (MQW) lasers. Properties of the strained MQW active region are simulated by eight-band kp calculations. Then, a 2D simulation along the transverse cross section of the device is performed based on a drift-diffusion model, which is self-consistently coupled to heat transport and(More)
The design of modern semiconductor devices requires the numerical simulation of basic fabrication steps. We investigate some electrooreactionndiiusion equations which describe the redistribution of charged dopants and point defects in semiconductor structures and which the simulations should be based on. Especially, we are interested in pair diiusion(More)
The paper deals with two-dimensional stationary energy models for semiconductor devices, which contain incompletely ionized impurities. We reduce the problem to a strongly coupled nonlinear system of four equations, which is elliptic in nondegenerated states. Heterostructures as well as mixed boundary conditions have to be taken into account. For boundary(More)
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