Picosecond GaAs-based photoconductive optoelectronic detectors

Abstract

A novel material deposited by molecular beam epitaxy at low substrate temperatures using Ga and As4 beam fluxes has been used as the active layer for a high-speed photoconductive optoelectronic switch. The high-speed photoconductive performance of the material was assessed by fabricating two devices: an Auston switch and a photoconductive-gap switch with a coplanar transmission line. In a coplanar transmission line configuration, the speed of response is 1.6 ps (full width at half maximum) and the response is 10 to 100 times greater than that of conventional photoconductive switches. Since the material is compatible with GaAs discrete device and integrated circuit technologies, this photoconductive switch may find extensive applications for high-speed device and circuit testing.

Continuous wave terahertz radiation from an InAs/GaAs quantum-dot photomixer device

“…7,8 Photocarrier lifetimes here are limited by controllably introducing lattice deformations either during epitaxial growth or with post-process ion bombardment. However, this also means that several compromises are made in the materials' performance such as low carrier mobilities and poor thermal conductivity.…”

Femtosecond differential transmission measurements on low temperature GaAs metal–semiconductor–metal structures

“…2,3 The possibility of achieving an epitaxial layer with a high breakdown field, high resistivity, and short carrier lifetime qualifies this material in a unique way for the fabrication of sensitive, fast photoconductive switches. In addition, investigations of carrier dynamics under high electric fields are possible.…”

Optoelectronic applications of LTMBE III–V materials

“…Typically, the optimum GaAs layer for optoelectronics is grown by molecular beam epitaxy at low substrate temperatures ( ~ 190-210 °C) at a growth rate of 1 ~m h-l [12]. This substrate temperature, the group III-V flux ratio, the growth rate, the film thickness and perhaps even other more subtle parameters are all important in determining the growth mechanism and quality of the epitaxial layers.…”