A novel mesfet‐compatible gaas optoelectronic switch

Abstract

Photoconductive optoelectronic pulse‐forming switches have been fabricated from vapor‐phase epitaxially grown GaAs‐based layer structures. The fabrication process is compatible with the MESFET/MMIC technology. The light‐absorbing region is thinned by chemical etching, thus changing the actual carrier lifetime in this region. The switches showed off/on resistance ratios of about 500 even at about 0.1‐mW incident optical power. The pulse response of the devices is limited by the lifetime of charge carriers.

Gain Studies on Photoconductors Made on Partly Compensated GaAs

“…However, in samples A and B, β approaches even -0.3, indicating a trap-assisted gain. The traps also caused a long tail in the pulse response of our devices [3]. The correlation with dark current is worth noting: the traps that cause the ,Q N -0.3 values, decrease also the dark current by trapping mobile carriers.…”

“…In this work, we report on the gain behavior of GaAs photoconductors realized on partly compensated material. The device is essentially a gateless MESFET, where the channel and a part of the buffer layer is removed by chemical etching [3]. The layer structure consists of a 3 pm nominally undoped buffer layer and a 0.3 pm n-type layer doped to 4 x 10 17 cm-3, all grown by vapor-phase epitaxy (VPE).…”