Publication

Synchrotron Radiation-Induced Surface Photovoltage at Metal/Gaas Interfaces

Giorgio Margaritondo
1991
Journal Articles

Abstract

We use the Kelvin method to study the synchrotron radiation induced surface photovoltage (SPV) on GaAs(110) as a function of metal coverage and temperature. We find that varying the temperature alone does not induce significant change in band bending in the semiconductor, but that the combination of low temperature and synchrotron light illumination on lightly doped n-GaAs induces a large and quasi-permanent SPV. On lightly doped n-GaAs, the low-temperature SPV (0.55 eV) is equal to the quasi-totality of the band bending at submonolayer coverage and discharges with a time constant of the order of hours. Above a monolayer, the rate of discharging increases dramatically, emphasizing the role of charge leakage through the overlayer. The room temperature SPV is considerably smaller (0.2 eV). Finally, no significant SPV is detected on highly doped GaAs. The impact of this synchrotron radiation induced SPV on the photoemission study of metal/semiconductor interfaces is discussed in detail.

Official source

https://infoscience.epfl.ch/entities/publication/745db9bf-dc1e-4f3d-903f-635c806adad6

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Giorgio Margaritondo
1991
Journal Articles

Abstract

Official source

https://infoscience.epfl.ch/entities/publication/745db9bf-dc1e-4f3d-903f-635c806adad6

About this result

Related concepts (32)

Gallium arsenide

Gallium arsenide (GaAs) is a III-V direct band gap semiconductor with a zinc blende crystal structure. Gallium arsenide is used in the manufacture of devices such as microwave frequency integrated circuits, monolithic microwave integrated circuits, infrared light-emitting diodes, laser diodes, solar cells and optical windows. GaAs is often used as a substrate material for the epitaxial growth of other III-V semiconductors, including indium gallium arsenide, aluminum gallium arsenide and others.

Ohmic contact

An ohmic contact is a non-rectifying electrical junction: a junction between two conductors that has a linear current–voltage (I–V) curve as with Ohm's law. Low-resistance ohmic contacts are used to allow charge to flow easily in both directions between the two conductors, without blocking due to rectification or excess power dissipation due to voltage thresholds. By contrast, a junction or contact that does not demonstrate a linear I–V curve is called non-ohmic.

Metal–semiconductor junction

In solid-state physics, a metal–semiconductor (M–S) junction is a type of electrical junction in which a metal comes in close contact with a semiconductor material. It is the oldest practical semiconductor device. M–S junctions can either be rectifying or non-rectifying. The rectifying metal–semiconductor junction forms a Schottky barrier, making a device known as a Schottky diode, while the non-rectifying junction is called an ohmic contact.

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