Modification of GaAs surface by low-current Townsend discharge

Abstract

Abstract. Influence of stationary spatially-homogeneous Townsend discharge on the (100) surface of semi-insulating GaAs samples is studied. Samples exposed to both electrons and ions in nitrogen discharge at the current density j=60 µA/cm 2 are studied by means of X-ray photoelectron spectroscopy, ellipsometry and atomic force microscopy. It is shown that exposure to low-energy ions (< 1 eV) changes crystal structure of the semiconductor on the depth up to 10-20 nm, although the stoichiometric composition does not change. The exposure to low-energy electrons (< 10 eV) forms an oxide layer, which is 5-10 nm thick. Atomic force microscopy demonstrates that the change in the surface potential of the samples may exceed 100 mV, for the both discharge polarities, while the surface roughness does not increase.

Exploration of the Townsend regime by discharge light emission in a gas discharge device

“…In fact, a better pattern is obtained at U = 780 V. In the Townsend mode, large numbers of electrons are produced with the increasing voltage, as also seen in Ref. [16]. The maximum electron density is observed near the anode and it radiates the corresponding DLE in this mode.…”

“…[11][12][13][14][15] In the above applications, the interactions of the materials, namely, semiconductors, metals, polymers and dielectrics with gas discharge, cause some differences in their ordinary features because of the surface modification. [16] It has also been known that any change in the emission of electron features of cathodes under the discharge may be undesirable and yield some spatio-temporal instabilities as functions of the system parameters. [16] There are two modes for the discharge, namely, Townsend and glow discharges.…”

“…[16] It has also been known that any change in the emission of electron features of cathodes under the discharge may be undesirable and yield some spatio-temporal instabilities as functions of the system parameters. [16] There are two modes for the discharge, namely, Townsend and glow discharges. [17] The Townsend discharge is a very weak discharge with a low space charge production (i.e., current).…”