Electron capture cross sections of InAs∕GaAs quantum dots

Engström, Olof; Kaniewska, M.; Fu, Ying; Piscator, Johan; Malmkvist, Mikael

doi:10.1063/1.1802377

Cited by 36 publications

(17 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore, by careful adjustment of the filling/reverse biases, electrons from the two intrinsic s states have been resolved successfully by this technique. [19][20][21] More importantly, the DLTS technique allows reliable determination of both the spatial and energy positions of nonradiative deep levels. Walther et al 22 observed energy states approximately 400 meV below the GaAs conduction band edge in or near the quantum dots, and Wang et al 6 and Krispin et al 23 reported a series of defect states in their InAs/ GaAs structures.…”

mentioning

confidence: 99%

“…The electrical space-charge technique, deep level transient spectroscopy ͑DLTS͒, 14 has recently been used to characterize QD structures, but most efforts have been focused on the intrinsic QD states. [15][16][17][18][19][20][21] The electrons can be thermally emitted out from the dots and then be detected by DLTS only when their electronic states are lifted above the bulk Fermi level. Therefore, by careful adjustment of the filling/reverse biases, electrons from the two intrinsic s states have been resolved successfully by this technique.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Coexistence of deep levels with optically active InAs quantum dots

et al. 2005

View full text Add to dashboard Cite

We present direct experimental evidence of the coexistence of deep levels with intrinsic quantum confinement states in large, self-assembled InAs quantum dots embedded in a GaAs matrix. The InAs quantum dots show very good optical properties, as evidenced by the strong photoluminescence at room temperature at ϳ1.3 m. Deep levels 160 and 484 meV below the GaAs conduction band edge have been identified at large reverse biases and high temperatures using deep level transient spectroscopy ͑DLTS͒ measurements. The reverse-bias dependence of the DLTS signal together with experimental results from the reference samples, containing thin InAs layers but no quantum dots, confirms that the deep levels coexist in the same layer as the InAs dots, and are most likely caused by the strain field during the lattice mismatched growth process. The densities of the deep levels in the structure are comparable to the density of the optically active quantum dots.Considerable efforts have been expended in the study of self-assembled semiconductor quantum dots ͑QDs͒, grown by the Stranski-Krastanov growth mode, because of their importance in device applications and in fundamental physics. 1,2 The excellent optical properties, such as strong photoluminescence ͑PL͒ intensity, are generally attributed to the coherent nature, i.e., defect free, of the QD islands. 1-6 In recent years, however, an increasing number of experiments have suggested the possibility that electronic deep levels might exist around or in what were regarded as coherent QDs that exhibit strong PL signals. For example, the presence of defects was suggested as a possible reason for the absence of the so-called phonon-bottleneck effect. 7,8 Other optical experiments, such as the quenching of PL signals at high temperatures, also suggested the possible existence of deep level defects around the QDs. 9-11 Dai et al. pointed out that the defect related centers existed at the InAs/ GaAs interface and played an important role in the PL quenching process. 12 They also indicated that the energy of the interface defects depended on the size of the quantum dots. By performing timeresolved optical characterizations of InAs QDs in GaAs, Fiore et al. speculated on the existence of nonradiative traps in the ͑In͒GaAs matrix in the close vicinity of the QDs, which would capture the carriers before they relaxed into the QDs. 13 Despite the evidence of the existence of unknown deep levels, the optical experiments could not provide confirmation and direct information, such as energy levels and concentrations, of possible deep levels due to their generally nonradiative nature. The electrical space-charge technique, deep level transient spectroscopy ͑DLTS͒, 14 has recently been used to characterize QD structures, but most efforts have been focused on the intrinsic QD states. 15-21 The electrons can be thermally emitted out from the dots and then be detected by DLTS only when their electronic states are lifted above the bulk Fermi level. Therefore, by careful adjustment of the filling/reverse b...

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Coexistence of deep levels with optically active InAs quantum dots

et al. 2005

View full text Add to dashboard Cite

show abstract

“…However, these optical experiments could not provide direct confirmation and information, such as the energy levels and concentrations, of possible deep levels due to their generally nonradiative nature. The electrical space-charge technique, deep-level transient spectroscopy (DLTS), has recently been used to reliably determine both the spatial and energy positions of intrinsic QD states as well as the nonradiative deep levels [7][8][9]. By carefully choosing the filling/reverse biases, electrons at the Fermi Level can charge/discharge different electronic states selectively by this technique.…”

mentioning

confidence: 99%

Laplace DLTS studies on deep levels coexisted with InAs quantum dots

Lin

Peaker

Song

2006

Phys. Status Solidi (c)

View full text Add to dashboard Cite

Self-assembled InAs/GaAs quantum dot structures have been investigated in both conventional and Laplace-transform deep-level transient spectroscopy (DLTS) experiments. Laplace DLTS technique provides orders of magnitude better energy resolution than conventional DLTS and hence enables us to study the electronic fine structure of the deep level states that are revealed using the conventional DLTS method. Two well-separated peaks corresponding to excitation energies of 468 meV and 485 meV are determined in the quantum dot sample, which have energy broadenings of 13.7 meV and 22.9 meV, respectively. A fine structure is also observed in the reference sample, but the ratio between the two peaks differs and the energy broadening is too narrow to be resolved even by the Laplace DLTS. The strain relaxation due to the QD formation is proposed to explain our observations.

show abstract

“…Authors of main part of papers present experimental results of the investigation of the C-V dependences for structures with QDs layers and determination such parameters of QDs, as concentration, energetic position and capture cross-section. They discussed considerably widespread peculiarities of C-V dependences of the Schottky structures with well-known shelf in such dependences connected with charge accumulation in QDs states [3][4][5][6] . A number of authors proposed some methods for the detail calculation of the capacitance and compared experimental and theoretical results [7][8][9] .…”

Section: Introductionmentioning

confidence: 99%

“…Because of the new abilities to accumulate the carriers of a charge in the QDs which could built into various semiconductor heterojunctions such structures are capable to show the certain physical phenomenon connected with charge of QDs and reveal some specific features in capacitance-voltage (C-V) dependences [1][2][3][4][5][6] . Authors of main part of papers present experimental results of the investigation of the C-V dependences for structures with QDs layers and determination such parameters of QDs, as concentration, energetic position and capture cross-section.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Negative Differential Capacitance-Voltage Dependences of Shottky Diode Structures With Gaas/Inas QDS

Lin

Lee

Ilchenko

et al. 2014

SEMST

View full text Add to dashboard Cite

Ñapacitance-voltage investigations were made on Schottky diodes with embedded GaAs/InAs quantum dots and quantum wells. An effect of the negative differential capacitance(NDC) was clear observed. Numerical modeling of the C-V dependences was carried out with temperature and concentration of QDs as parameters. Energy structure of the investigated samples was examined by deep level transient spectroscopy(DLTS). It was shown that the proposed model is in good agreement with experiment and describes well the NDC effect.

show abstract

Electron capture cross sections of InAs∕GaAs quantum dots

Cited by 36 publications

References 15 publications

Coexistence of deep levels with optically active InAs quantum dots

Coexistence of deep levels with optically active InAs quantum dots

Laplace DLTS studies on deep levels coexisted with InAs quantum dots

Investigation of Negative Differential Capacitance-Voltage Dependences of Shottky Diode Structures With Gaas/Inas QDS

Contact Info

Product

Resources

About