Differential capacitance measurements of relaxation-induced defects in InGaAs/GaAs Schottky diodes

Chen, Jenn–Fang; Chen, N. C.; Wang, Jiin-Shung; Chen, Y.F.

doi:10.1109/16.902717

Cited by 6 publications

(2 citation statements)

References 13 publications

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“…This can be seen from the frequency dependence of the C dispersion in figure 2(a). This dispersion is not due to a resistancecapacitance (RC) time constant effect [18], since it is observed in the QD region, rather than in the top GaAs layer except the parallel shift. The RC time constant determined from capacitance-frequency measurements at −0.5 V is about 10 −6 s and is nearly temperature and voltage independent.…”

Section: Electron Emission From a Qdmentioning

confidence: 95%

Relaxation-induced lattice misfits and their effects on the emission properties of InAs quantum dots

et al. 2007

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Strain relaxation in InAs/InGaAs quantum dots (QDs) is shown to introduce misfits in the QD and neighboring GaAs bottom layer. A capacitance-voltage profiling shows an electron accumulation peak at the QD with a long emission time, followed by additional carrier depletion caused by the misfits in the GaAs bottom layer. The emission-time increase is explained by the suppression of tunneling for the QD excited states due to the additional carrier depletion. As a result, electrons are thermally activated from the QD states to the GaAs conduction band, consistent with observed emission energies of 0.160 and 0.068 eV which are comparable to the confinement energies of the QD electron ground and first-excited states, respectively, relative to the GaAs conduction band. This is in contrast to non-relaxed samples in which emission energy of 60 meV is observed, corresponding to the emission from the QD ground state to the first-excited state.

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Section: Electron Emission From a Qdmentioning

confidence: 95%

Relaxation-induced lattice misfits and their effects on the emission properties of InAs quantum dots

et al. 2007

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“…Figure 4 shows these time constants whose activation energies are obtained to be 0.08 and 0.13 eV for À0:5 and À1 V, respectively. These time constants (4 Â 10 À6 s at 300 K) correspond to geometric RC time constants, 22) where R is caused by the carrier depletion in the QD region. From the value of C [¼ 300 pF at À1 V from the inset of Fig.…”

Section: Electron Emission From Inasn Qdmentioning

confidence: 99%

Effect of Nitrogen Incorporation into InAs layer in InAs/InGaAs Self-Assembled Quantum Dots

Chen¹,

Hsiao²,

Chen³

et al. 2005

Jpn. J. Appl. Phys.

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We present the results of nitrogen incorporation into the InAs layer in InAs/InGaAs quantum dots (QDs). We show that this incorporation causes an asymmetric photoluminescence (PL) line shape and abnormally large redshift of the PL peak from the quantum dots as temperature increases. In addition, this incorporation causes a large series resistance and a rapid increase in reverse current at a bias corresponding to the QD region. This effect is due to the formation of a deep trap at 0.34 -0.41 eV, which depletes the carriers in the QD region. This depletion gives rise to a geometric resistance-capacitance time-constant effect for the ac conductivity of the free electrons in the top GaAs layer. This trap markedly alters the emission properties of the QD structure. The ac conductivity of the QD structure is governed by the thermal activation of trapped electrons rather than the electron emission from the QD confined states. This incorporation significantly increases the electron emission time from the QD region and, thus, can be used intentionally to modify the emission properties of the QD structure.

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Compensation effect and differential capacitance analysis of electronic energy band structure in relaxed InAs quantum dots

Chen

Chiang

et al. 2010

Journal of Applied Physics

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Articles you may be interested inElectronic structure of self-assembled InGaAs/GaAs quantum rings studied by capacitance-voltage spectroscopy Appl. Phys. Lett. 96, 033111 (2010); 10.1063/1.3293445 Electron emission properties of relaxation-induced traps in InAs/GaAs quantum dots and the effect of electronic band structureThe use of a differential capacitance technique for analyzing the effect of strain relaxation on the electronic energy band structure in relaxed InAs self-assembled quantum dots ͑QDs͒ is presented. Strain relaxation is shown to induce a deep defect state and compensate the ionized impurity in the bottom GaAs layer, leading to a double depletion width and a long emission time. An expression of capacitance at different frequency and voltage is derived for analyzing the experimental data. It has been shown that the relationship between the low-frequency and high-frequency capacitances can be well explained by a Schottky depletion model with a compensated concentration in the bottom GaAs layer. A simple expression is presented to account for the modulation of the free electrons in the top GaAs layer. This capacitance analysis shows a long low-energy tail for the electron ground state, suggesting not very uniform strain relaxation. The results of this study illustrate a carrier compensation effect of the defect state on the electronic energy band structure near the QDs.

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Differential capacitance measurements of relaxation-induced defects in InGaAs/GaAs Schottky diodes

Cited by 6 publications

References 13 publications

Relaxation-induced lattice misfits and their effects on the emission properties of InAs quantum dots

Relaxation-induced lattice misfits and their effects on the emission properties of InAs quantum dots

Effect of Nitrogen Incorporation into InAs layer in InAs/InGaAs Self-Assembled Quantum Dots

Compensation effect and differential capacitance analysis of electronic energy band structure in relaxed InAs quantum dots

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