Daimler Chrysler Ag

Daimler-Benz Ag

Hartmut Presting

Horst Kibbel

Lorenzo Colace

Ulf Konig

Andreas Gruhle

Gianlorenzo Masini

Milan Jaros

Johannes Konle

Ulf Koenig

Thomas Pearsall

A silicon-germanium thin-film solar cell having a quantum well structure as an active base layer within the space-charge region of the silicon p-n diode junction. The quantum well structure is composed of a sequence of silicon and germanium layers. In this manner, a highly absorbent base layer is produced in a silicon solar cell.

Silicon-germanium solar cell having a high power efficiency

A voltage-controlled, wavelenght-selective photodetector includes comprising a double diode having a counter-polarized Si-Schottky diode and a SiGe PIN diode. The short-wave portion (&lgr;<0.9 &mgr;m) of the light entering the detector through a window generates electron-hole pairs in the Si-Schottky diode, while the longer-wave portion (1 &mgr;m<&lgr;<2 &mgr;m) passes through the substrate and is absorbed in the epitaxially deposited SiGe superlattice or the quantum well diode. The photocurrents of both detectors flow in physically opposite directions and subtract from each other, resulting in a wavelength-dependent operational sign of the photocurrent. The level of the bias voltage applied determines whether the photocurrent of the Si-Schottky diode or the photocurrent of the Si/Ge PIN diode determines the spectrum. This can be used, for example, in an application for decoding signals by transforming the light signal into an electrical output signal and subtracting the photocurrents of the two detectors which filters out the noise component and thus raises the signal/noise ratio of a light signal.

Voltage-controlled wavelength-selective photodetector

A photodetector which can be operated in two wavelength ranges and is comprised of two detectors (A, B) arranged one on top of the other. A Si Schottky diode forms detector A which absorbs light in a region .lambda.&lt;0.9 .mu.m. Longer-waved light (1 .mu.m&lt;.lambda.&lt;2 .mu.m) is absorbed in detector B which is comprised of an Si/SiGe pn-diode. To increase the efficiency, detector B is made with an integrated resonator. A further increase of the efficiency of the photodetector is accomplished through the mounting of a Bragg reflector on the absorbing layer of detector B.

SiGe photodetector with high efficiency

A valence band quantum-well structure with a modulation doping for an optical-component implemented in Si technology. With this component, a high quantum efficiency and detection efficiency are accomplished. By way of spatial separation of the doped zone from the almost undoped SiGe quantum well, the Coulomb scattering and the recombination probability of the charge carriers drifting in the externally applied electrical field is greatly reduced at the doping material cores.

Optoelectronic component having a modulation-doped layer structure

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Blaustein, Germany

Hartmut Presting