Scanning tunneling microscopy and spectroscopy of arsenic antisites in low temperature grown InGaAs

Abstract

Scanning tunneling microscopy is used to study low temperature grown (LTG) InGaAs with and without Be doping. The Be-doped material is observed to contain significantly fewer AsGa antisite defects than the undoped material, with no evidence found for Be–As complexes. Annealing of the LTG-InGaAs forms precipitates preferentially in the undoped material. The previously observed dependence of the optical response time on Be doping and annealing is attributed to changes in the As antisite concentration and the compensation effect of the Be.

Terahertz detectors from Be-doped low-temperature grown InGaAs/InAlAs: Interplay of annealing and terahertz performance

“…On the one hand it was reported that annealing increased the electron lifetime due to the formation of arsenic clusters, similarly to LTG-GaAs. 27,28,35 On the other hand a recent study on annaled Be-doped LTG-InGaAs/InAlAs multilayer structures revealed a decrease of the electron lifetime for annealing temperatures between 350 • C and 600 • C. 34 In this publication we address this inconsistency and show that annealing indeed increases the electron lifetime due to the precipitation of arsenic antisites.…”

“…First, we notice that the electron lifetime decreases for higher Be doping concentrations since Be dopants ionize additional antisite defects, which in turn increases the density of fast trapping centers. 28,29,31 Furthermore, the fact that Be dopants ionize additional antisites explains why the conductivity of all the samples shown in Fig. 2 was electron-like, although the Be doping concentration was up to two orders of magnitude higher than the residual electron concentration of the undoped material.…”

“…2 was electron-like, although the Be doping concentration was up to two orders of magnitude higher than the residual electron concentration of the undoped material. 28,31 Apart from these well-known effects of Be-doping Fig. 3 shows that annealing increases the electron lifetime of all samples.…”

“…27 Apart from the pure compensatory effect of Be-doping, the electron lifetime in LTG-InGaAs decreases for a higher Be-doping concentration due to the ionization of additional As Ga defects by Be dopants. 28,29 Electron lifetimes below 0.5 ps were measured in LTG-InGaAs:Be. However, carrier concentrations below 1 × 10 14 cm -3 could only be obtained by an additional annealing step in combination with the growth of a multilayer heterostructure consisting of Be-doped InGaAs and Be-doped InAlAs.…”

Генерация и детектирование терагерцевого излучения в низкотемпературных эпитаксиальных пленках GaAs на подложках GaAs с ориентациями (100) и (111)A

“…Вследствие этого пленка LT-GaAs обладает высокой концентрацией антиструктурных дефектов As Ga (атом As в узле атома Ga) порядка 10 20 см −3 [6]. В заряженном состоянии As + Ga эти дефекты действуют как ловушки для электронов и тем самым обеспечивают крайне малое время жизни фотовозбужденных электронов (менее пи-косекунды) [7].…”