Discontinuities and Hysteresis in the I–V Characteristics of n-GaAs at Low Temperatures

Abstract

We present experimental investigations of current filamentation in n‐GaAs films in the regime of low‐temperature impurity breakdown. Using a laser‐scanning microscope, we were able to reconstruct current filaments in biasing regions of multistability. It is shown that discontinuities and hysteresis frequently observed in current–voltage characteristics are due to the interaction of filaments with material imperfections. In particular filaments remain in energetically unfavourable configurations when squeezed or pinned by defects.

Electron mobility measurement inn−GaAsat low-temperature impurity breakdown

“…An analogous filament-pinning effect may be observed also due to material imperfections. 19,20 The arrangement of filaments in Figs. 1͑a͒ and 1͑b͒ are obtained for the same current.…”

“…The vertical part of the characteristic reflects abrupt changes in the filament arrangement, as well as the continuous growth of filament widths. 19,20 The sample conductivity becomes almost constant as the whole width of the sample becomes filled with the high-conducting phase. Upon applying a perpendicular magnetic field the filaments are bent and tilted due to the Lorentz force, 15 as seen in Fig.…”