Publication

Optical-Properties and Switching Behavior of Excited Iii-V Semiconductors near the Direct Indirect Cross-Over

Jean-Louis Staehli
1992
Journal Articles

Abstract

In highly excited semiconductor systems near the transition from direct to indirect band structure (cross-over) the energetic distance between different conduction band minima is a nonmonotonous function of the excitation intensity. A theoretical explanation of this experimental result is given. Our investigations are based on the evaluation of photoluminescence spectra using a careful lineshape analysis. The nonmonotony is a consequence of the unequal shrinkage of the direct and indirect gaps as a function of the population of energetically comparable conduction band valleys in a material near cross-over. In the situation discussed an optical switching mechanism is expected, which is explained with special respect to its switching time. Important problems of electron-electron interaction are discussed.

Official source

https://infoscience.epfl.ch/entities/publication/aac2b876-9d62-47ca-bca4-3186897a0a21

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Jean-Louis Staehli
1992
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/aac2b876-9d62-47ca-bca4-3186897a0a21

About this result

Related concepts (32)

Direct and indirect band gaps

In semiconductor physics, the band gap of a semiconductor can be of two basic types, a direct band gap or an indirect band gap. The minimal-energy state in the conduction band and the maximal-energy state in the valence band are each characterized by a certain crystal momentum (k-vector) in the Brillouin zone. If the k-vectors are different, the material has an "indirect gap". The band gap is called "direct" if the crystal momentum of electrons and holes is the same in both the conduction band and the valence band; an electron can directly emit a photon.

Wide-bandgap semiconductor

Wide-bandgap semiconductors (also known as WBG semiconductors or WBGSs) are semiconductor materials which have a larger band gap than conventional semiconductors. Conventional semiconductors like silicon have a bandgap in the range of 0.6 – 1.5 electronvolt (eV), whereas wide-bandgap materials have bandgaps in the range above 2 eV. Generally, wide-bandgap semiconductors have electronic properties which fall in between those of conventional semiconductors and insulators.

Band gap

In solid-state physics and solid-state chemistry, a band gap, also called a bandgap or energy gap, is an energy range in a solid where no electronic states exist. In graphs of the electronic band structure of solids, the band gap refers to the energy difference (often expressed in electronvolts) between the top of the valence band and the bottom of the conduction band in insulators and semiconductors. It is the energy required to promote an electron from the valence band to the conduction band.

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Optical-Properties and Switching Behavior of Excited Iii-V Semiconductors near the Direct Indirect Cross-Over

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