Impurity breakdown and electric-field-dependent luminescence in MBE and VPE GaAs layers

Abstract

Impurity avalanche breakdown in n-type GaAs layers prepared by t h e LPE, VPE and MBE methods has been studied in detail using voltage-controlled current-voltage (1-V) characteristics and luminescence measurements together with computer simulations. Scholl's model of the first-order non-equilibrium phase transition in a two-level system was found to be adequate to describe the main experimental results. The threshold voltage for breakdown depends on the initial free-electron concentration. The hysteresis width diminishes with decreasing binding energy of electrons in the excited states of donors. The changes in luminescence spectra observed during impurity breakdown reflect changes in the charge state of shallow impurities. The band corresponding to B A transitions disappears together with t h e decrease of the exciton radiative recombination rate.In the post-breakdown part of t h e I-V characteristics another region 01 nonlinear behaviour with hysteresis and sharp increase of instabilities was observed. Its origin has not yet been determined unambiguously.

Influence of Impact Ionization of Shallow Donors on Luminescence in GaAs

“…The observed decrease in luminescence intensity with an increase in the electric field is consistent with literature data [8,9]. From Fig.…”

“…a permanent illumination and high electric fields, are also adequate for studying an influence of impact ionization of shallow donors on the near-band luminescence in this material. Such studies were performed by others on n-type GaAs samples and described in a number of papers [6][7][8][9]. The aim of the present study is to compare an influence of impact ionization on luminescence in n-type and SI GaAs.…”

Peculiarities of high electric field conduction in p-type diamond

“…This is further confirmed by the linearity of breakdown voltage with the inter electrode gap which clearly indicates an electric field dependent phenomenon. The breakdown voltage increases as acceptor concentration decreases (see Table I) which is opposite to classic work 15 . Indeed concentration of majority and minority impurities, i.e.…”

Visualization of current filaments in n-GaAs by photoluminescence quenching

“…5 The effect of an external magnetic field on filaments has been investigated by a scanning laser microscope. [9][10][11] Ryabushkin et al 12 reported a strong spatial variation, in a direction perpendicular to the current flow, of photoluminescence emitted by n-GaAs epitaxial layers in the filamentary current regime. Irradiation destabilizes the current flow especially at the filament borders.…”