Recombination at dislocations

Figielski, T.

doi:10.1016/0038-1101(78)90216-2

Cited by 108 publications

(33 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…[26,37,38] for a full discussion. Under steady state conditions, expressions for the net concentrations δm of holes trapped at dislocations, for the excess concentration δn of electrons in the conduction band, and for the excess hole concentration δp in the valence band can be derived from rate equations involving a potential barrier between charged line defects and the semiconductor [26,38,39]. At a finite temperature, trapped carriers can either be released and contribute to the radiative IB recombination, or contribute to the DPL emission, or recombine nonradiatively at the dislocation site.…”

Section: Temperature Dependence Of Interband and Dislocation Relatmentioning

confidence: 99%

Ge Crystals on Si Show Their Light

et al. 2014

View full text Add to dashboard Cite

We report micron-sized Ge crystal arrays grown on deeply patterned Si substrates that yield a surge of the interband photoluminescence intensity by more than 2 orders of magnitude with respect to that typical for epitaxial layers directly grown on planar substrates. This finding is ascribed to the strongly modified internal quantum efficiency induced by controlling the nonradiative recombination at dislocations and to the improved light extraction offered by the array architecture. By spectrally resolving the interband and the dislocation-related luminescence, we address the parasitic activity of extended defects and its impact on the optical properties of the heterosystem. Such results are then exploited along with band gap engineering to design SiGe reflectors and Ge quantum wells that are effective in further amplifying the emission yield.

show abstract

Section: Temperature Dependence Of Interband and Dislocation Relatmentioning

confidence: 99%

Ge Crystals on Si Show Their Light

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Such PL behavior is a hallmark of valley repopulation induced by thermal emission of carriers from the defect sites. 20,31 Remarkably, the passivation results in a pronounced increase in the high temperature regime, yielding a room temperature PL spectrum with nearly twice the emission intensity of the as-grown Ge micro-crystals. As a comparison, we note that insertion of the SiGe barriers leads to less than 10% increase in the integrated PL intensity as compared to the as-grown Ge microcrystals.…”

Section: à2mentioning

confidence: 99%

Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates

Pezzoli

Giorgioni

Gallacher

et al. 2016

Applied Physics Letters

View full text Add to dashboard Cite

We address nonradiative recombination pathways by leveraging surface passivation and dislocation management in µm-scale arrays of Ge crystals grown on deeply patterned Si substrates. The time decay photoluminescence (PL) at cryogenic temperatures discloses carrier lifetimes approaching 45 ns in band-gap engineered Ge micro-crystals. This investigation provides compelling information about the competitive interplay between the radiative band-edge transitions and the trapping of carriers by dislocations and free surfaces. Furthermore, an in-depth analysis of the temperature dependence of the PL, combined with capacitance data and finite difference time domain modeling, demonstrates the effectiveness of GeO2 in passivating the surface of Ge and thus in enhancing the room temperature PL emission.

show abstract

“…On the contrary, deep levels related to dislocations are distinguished by logarithmic capture kinetics [4,5]. Such a kinetics results from the formation of a Coulombic barrier around the charged dislocations whose height increases with the filling-pulse duration [6]. …”

mentioning

confidence: 99%

Capture kinetics at deep‐level electron traps in GaN‐based laser diode

Yastrubchak

Wosiński

Mąkοsa

et al. 2007

Phys. Status Solidi (c)

Self Cite

View full text Add to dashboard Cite

Two deep-level electron traps, E1 at E C − 0.23 eV and E2 at E C − 0.55 eV, have been revealed by means of deep-level transient spectroscopy (DLTS) in a GaN-based laser-diode heterostructure grown by metalorganic vapour-phase epitaxy on a bulk GaN substrate. The two traps represent different electron capture behaviours. The E1 trap, which exhibits the logarithmic capture kinetics and the DLTS-line shape characteristic of band-like electron states, is attributed to the core states of threading dislocations in a p-type layer of the structure. In contrast, the E2 trap, being the most prominent deep-level electron trap in GaN layers, displays the exponential capture kinetics and is assigned to isolated point defects, likely the nitrogen antisite defect.1 Introduction GaN-based III-V nitrides (GaN, InGaN and AlGaN) are wide direct band-gap semiconductors, which have already been applied successfully to optoelectronic devices, such as highbrightness blue light emitting diodes and lasers and solar-blind ultraviolet detectors [1]. Because of low thermal generation of charge carriers and large dielectric breakdown fields of these materials they have also found applications in high-temperature and high-power electronics [2]. However, owing to the large dislocation densities in the GaN epitaxial layers, commonly grown on highly-mismatched sapphire substrates, and self-compensation tendencies of wide band-gap semiconductors, a number of deep-level defects, affecting the performance and reliability of GaN-based devices, are usually present in the layers. Identification and understanding of these defects, especially dislocations, is of particular importance for improving the device technology.Deep-level transient spectroscopy (DLTS) is commonly used from already three decades as a powerful experimental technique for investigations of deep-level defects in semiconductor materials and structures. It allows characterizing and cataloguing deep levels by means of their capture cross-section and activation energy of thermal emission of charge carriers form the levels [3]. Additional information on the structure of deep-level defects can be gained while measuring the kinetics for capture of charge carriers into the defect states by means of recording the dependence of the DLTS-signal amplitude on the filling-pulse duration. In this respect, deep levels associated with extended defects, such as dislocations, distinctly differ from deep levels associated with isolated point defects or impurities, which exhibit exponential capture kinetics. On the contrary, deep levels related to dislocations are distinguished by logarithmic capture kinetics [4,5]. Such a kinetics results from the formation of a Coulombic barrier around the charged dislocations whose height increases with the filling-pulse duration [6].

show abstract

Recombination at dislocations

Cited by 108 publications

References 16 publications

Ge Crystals on Si Show Their Light

Ge Crystals on Si Show Their Light

Disentangling nonradiative recombination processes in Ge micro-crystals on Si substrates

Capture kinetics at deep‐level electron traps in GaN‐based laser diode

Contact Info

Product

Resources

About