Capacitance-voltage profiling of Au/n-GaAs Schottky barrier structures containing a layer of self-organized InAs quantum dots

Brunkov, P. N.; Suvorova, Alexandra; Берт, Н. А.; Kovsh, A. R.; Zhukov, A. E.; Egorov, A. Yu.; Ustinov, V. M.; Tsatsulnikov, A. F.; Ledentsov, N. N.; Kop’ev, P. S.; Konnikov, S. G.; Eaves, L.; Main, P. C.

doi:10.1134/1.1187575

Cited by 31 publications

(24 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In such structures, the QDs are filled with electrons. 12,13 The independent capacitance-voltage measurements 13 showed that on average two resident electrons occupy each QD at low temperature in the n-i-n structure.…”

Section: Samples and Experimental Resultsmentioning

confidence: 99%

Optical spin polarization and exchange interaction in doubly charged InAs self-assembled quantum dots

et al. 2005

Self Cite

View full text Add to dashboard Cite

The work is an experimental study of optical spin polarization in InAs/ GaAs quantum dots ͑QDs͒ with two resident electrons or holes. A capture of a photogenerated electron-hole pair into such a QD creates a negative or positive tetron ͑doubly charged exciton͒. Spin polarization was registered by the circular polarization of the QD photoluminescence ͑PL͒. The spin state was found to be radically different in the dots with the opposite sign of the charge. Particularly, under excitation in a GaAs barrier, the polarization of the ground-state PL is negative ͑relative to the polarization of exciting light͒ in the negatively charged QDs and positive in the positively charged QDs. With increasing excitation intensity, the negative polarization rises from zero up to a saturation level, while the positive polarization decreases. The negative polarization increases in weak magnetic fields applied in Faraday geometry; however, it is suppressed in strong fields. The positive polarization always increases as a function of magnetic field. We propose a theoretical model that qualitatively explains the experimental results.

show abstract

Section: Samples and Experimental Resultsmentioning

confidence: 99%

Optical spin polarization and exchange interaction in doubly charged InAs self-assembled quantum dots

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…The independent capacitance−voltage measurements [12] showed that two equilibrium electrons per dot on an average occupy the dots at low temperature and zero bias. The MBE grown structure had a semitransparent gold Schottky contact on the top surface and an ohmic contact on the n + -GaAs substrate providing an application of an electric field to the structure and control the dot charge.…”

Section: Experiments and Discussionmentioning

confidence: 99%

Optical spin polarization in negatively charged InAs self‐assembled quantum dots under applied electric field

Kalevich¹,

Ikezawa²,

Okuno³

et al. 2003

Physica Status Solidi (b)

Self Cite

View full text Add to dashboard Cite

We have studied the influence of an external electric field on the optical spin polarization of initially negatively charged InAs/GaAs quantum dots (QDs). The spin polarization of the carriers was controlled by measuring the photoluminescence (PL) circular polarization. We have found that the PL polarization of the QD is negative under an excitation above the GaAs barrier, and that it becomes positive under an excitation below the barrier. An applied negative electric field destroys both positive and negative polarization. The time decay of the negative polarization was found from time-resolved measurements to exceed strongly the QD radiative lifetime. This fact indicates a long-living spin memory in the dots under study.1 Introduction Quantum dot structures, where carrier spin relaxation is greatly suppressed by quantum confinement, are proposed to be the basis for making pilot devices of spin electronics and quantum information processing [1,2]. However, an anisotropic exchange interaction of electrons and holes induced by the dot asymmetry can split the exciton radiative doublet and destroy spin polarization of QD excitons [3,4]. The anisotropic exchange interaction can be strongly suppressed in charged QDs [5−11]. This is obvious for QDs containing an odd number of carriers (including photo-created electron−hole pairs), since such QDs have a half-integer spin and the anisotropic exchange does not split spin states due to the Kramers theorem [9]. Indeed, a long-living spin orientation has been observed in δ-doped InAs QDs [5−7]. Spin memory variation in a long time interval was realized recently in negatively charged InP QDs by applying an electric field [8−11]. In spite of the great interest in spin polarization, an understanding of fine structure, spin states, and peculiarities of spin relaxation in QD's charged complexes is far to be complete. To our mind, the most promising and advanced step in this direction is the structure where the dot charge and, as a consequence, its fine structure and spin state, can be controlled by the external electric field.In the present work we have studied experimentally the influence of an external electric field on the optical spin polarization of initially negatively charged InAs/GaAs QDs. A strong dependence of the spin polarization on the applied bias has been observed. In particular, the spin relaxation time of electrons was found to exceed strongly their radiative lifetime when the dots are occupied by 2 equilibrium electrons on an average.

show abstract

“…If the temperature decreases the emission rate decreases and the step in the C-V characteristics becomes less significant. A quasistatic model based on the self-consistent solution of the Poisson equations is used to calculate the C-V curve [1]. The Poisson equation is solved for different values of reverse bias to obtain the charge in the structure per unit area.…”

Section: Resultsmentioning

confidence: 99%

“…The C-V characteristics measured for the reference diode exhibit bulk behaviour in contrast to the QDs sample for which a characteristic step corresponding to discharging of QDs is observed within broad range of temperatures. A quasistatic model based on the self-consistent solution of the Poisson equations is used to calculate the capacitance [1]. By comparison with experimental data the energy level of the QDs is evaluated.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Capacitance-Voltage Studies of Ti/p-ZnTe Schottky Barrier Structures Containing CdTe Quantum Dots

Płaczek‐Popko¹,

Szatkowski²,

Zielony³

et al. 2011

Acta Phys. Pol. A

View full text Add to dashboard Cite

In this paper the electronic states of self-organized CdTe quantum dots embedded in ZnTe matrix are studied by means of capacitance-voltage (C-V ) characteristics within the temperature range of 180-300 K. A reference diode of the same layer structure but without quantum dots is studied also for comparison. The C-V characteristics measured for the reference diode exhibit bulk behaviour in contrast to the quantum dots sample for which a characteristic step corresponding to discharging of quantum dots is clearly visible within broad range of temperatures. A quasistatic model based on the self-consistent solution of the Poisson equations is used to simulate the capacitance. By comparison the calculated C-V curve with experimental curve the apparent thermal activation energy for hole emission from the quantum dots to the ZnTe matrix is found to be equal to (0.12±0.03) eV.

show abstract

Capacitance-voltage profiling of Au/n-GaAs Schottky barrier structures containing a layer of self-organized InAs quantum dots

Cited by 31 publications

References 11 publications

Optical spin polarization and exchange interaction in doubly charged InAs self-assembled quantum dots

Optical spin polarization and exchange interaction in doubly charged InAs self-assembled quantum dots

Optical spin polarization in negatively charged InAs self‐assembled quantum dots under applied electric field

Capacitance-Voltage Studies of Ti/p-ZnTe Schottky Barrier Structures Containing CdTe Quantum Dots

Contact Info

Product

Resources

About