Photoconductivity investigation of the electron dynamics in GaAs grown at low temperature

Abstract

We present detailed measurements of photoconductivity as functions of illumination power and temperature on metal–semiconductor–metal photodetectors made of low-temperature GaAs grown at different temperatures (225–350 °C). The extracted carrier lifetimes show the expected dependence as a function of growth temperature. Additionally, our experiments show an order-of-magnitude variation of the extracted lifetimes as functions of measurement temperature and illumination intensity. We propose a simple model based on the one-center-Shockley Read-recombination equation which gives good qualitative agreement over the whole range of temperature (20–120 °C) and illumination power (2×10−4 to 20 W/cm2). We show that the recombination properties are determined by the exact position of the electronic quasi-Fermi level in the partially filled midgap donor band, which is strongly influenced by the acceptor concentration.

Low-temperature-grown GaAs: Modeling of transient reflectivity experiments

“…6, 21 We should note that doing this, we assumed that the defects were the same for all samples ͑annealed or not͒. 23 the deep-donor absorption cross section is fixed at DD =2ϫ 10 −16 cm 2 ͑which gives ␣ DD =5ϫ 10 3 cm −1 for N DD = 2.5ϫ 10 19 cm −3 ͒, and we have determined a unique best set of electron and hole crosssections ͑ n and p ͒ for all samples.…”

“…21,22 The rate equations concern an electron density in the conduction band n, a hole density in the valence band p, and a nonionized deep-donor density n DD . 21,22 The rate equations concern an electron density in the conduction band n, a hole density in the valence band p, and a nonionized deep-donor density n DD .…”

Low-temperature-grown GaAs coplanar waveguide single-photon/two photon absorption autocorrelator

“…͑8͒, (1) is the first order susceptibility associated with a constant index of refraction n or constant absorption coefficient. The second order susceptibility (2) is associated with second harmonic generation, which is not significant in our material.…”

Relaxation processes of photoexcited carriers in GaAs/AlAs multiple quantum well structures grown by molecular beam epitaxy at low temperatures

“…3 They found that the relationship predicted by Ruda and Shik was applicable. 4 As for excess As point defects, a number of studies have analyzed relaxation processes on the basis of rate equations, [5][6][7][8] but no study has reported a dependence of the carrier lifetime on experimentally determined concentrations of excess As point defects in LT-GaAs or LT-MQW. Only the dependence of the carrier lifetime on the growth temperature [9][10][11][12][13][14][15] or the flux conditions 16 has been investigated, and hence, its dependence on the excess As concentrations has been only qualitatively discussed to date.…”