Finite element modeling of extraordinary optoconductance in GaAs-In metal-semiconductor hybrid structures

• Published in: arXiv.org 2006-03
• Main Authors: Wieland, K A, Wang, Yun, Solin, S A, Girgis, A M, Ram-Mohan, L R
• Format: Article
• Language: English
• Subjects: Bias; Carrier mobility; Data acquisition; Electric potential; Finite element method; Hole distribution; Hybrid structures; Lasers; Mathematical models; Parameters; Temperature dependence
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0602149

We present a detailed discussion of extraordinary optoconductance (EOC). Experimental data was acquired via macroscopic metal-semiconductor hybrid structures composed of GaAs and In and subjected to illumination from an Ar ion laser. A drift diffusion model using the finite element method (FEM) provided a reasonable fit to the data. EOC is explored as a function of laser position, bias current, laser power density, and temperature. The positional dependence of the voltage is accounted for by the Dember effect, with the model incorporating the excess hole distribution based on the carrier mobility, and thus the mean free path. The bias current is found to produce a linear voltage offset and does not influence the EOC. A linear relationship is found between the laser power density and the voltage in the bare and hybrid devices. This dependence is reproduced in the model by a generation rate parameter which is related to the power density. Incorporating the mobility and diffusion temperature dependence, the model directly parallels the temperature dependence of the EOC without the use of fitting parameters.