What is bimolecular recombination?
Bimolecular recombination is defined as a second-order process, (10.2)Rrec=−dndt=kbrnp,where kbr is the bimolecular recombination rate coefficient, n is the electron density, and p is the hole density. From: Handbook of Organic Materials for Electronic and Photonic Devices (Second Edition), 2019.
What is SRH recombination?
In Shockley-Read-Hall recombination (SRH), also called trap-assisted recombination, the electron in transition between bands passes through a new energy state (localized state) created within the band gap by a dopant or a defect in the crystal lattice; such energy states are called traps.
What is semiconductor recombination?
Recombination is the mechanism that is utilized by extrinsic semiconductors to equilibrate excess charge carriers through the bringing together and annihilation of oppositely charged carriers. Specifically the annihilation of positively charged holes and negatively charged impurity or free electrons.
What is radiative and non radiative recombination?
Recombination mechanisms can in general be classified into two groups, radiative and nonradiative. Radiative recombination occurs when an electron in the conduction band recombines with a hole in the valence band and the excess energy is emitted in the form of a photon.
What is drift current in semiconductor?
Drift current is the electric current caused by particles getting pulled by an electric field. The term is most commonly used in the context of electrons and holes in semiconductors, although the same concept also applies to metals, electrolytes, and so on.
Is Shockley Read Hall recombination radiative?
Two main sources of non-radiative recombination are attributed to Shockley-Read-Hall (SRH) and Auger recombination.
What are the three carrier recombination mechanisms in semiconductors?
There are three types of recombination; Radiative, Defect, and Auger.
What is intrinsic semiconductor material?
An intrinsic (pure) semiconductor, also called an undoped semiconductor or i-type semiconductor, is a pure semiconductor without any significant dopant species present. The number of charge carriers is therefore determined by the properties of the material itself instead of the amount of impurities.
What causes non radiative recombination?
Most common cause for non-radiative recombination events are defects in the crystal structure. This effects include unwanted foreign atoms, native defects, dislocations. All such defects have energy level structure that are different from substantial semiconductor atoms.
What is non radiative?
The term nonradiative or radiationless transitions has been in common use for many decades to describe radiation-induced processes in which no energy is exchanged with the radiation field.
What is drift and diffusion in any semiconductor?
Diffusion current Density is a current in a semiconductor caused by the diffusion of charge carriers (holes and/or electrons). The drift current, by contrast, is due to the motion of charge carriers due to the force exerted on them by an electric field.
Bimolecular recombination is defined as a second-order process, (10.2)Rrec=−dndt=kbrnp,where kbr is the bimolecular recombination rate coefficient, n is the electron density, and p is the hole density. From: Handbook of Organic Materials for Electronic and Photonic Devices (Second Edition), 2019
How does temperature affect bimolecular charge recombination?
We show that the sharpening of photon, electron and hole distribution functions significantly enhances bimolecular charge recombination as the temperature is lowered, mirroring trends in transient spectroscopy.
How does charge carrier density affect the rate of recombination?
However, with increasing charge-carrier density, bimolecular (radiative) recombination between unbound electrons and holes will begin to take over, while at even higher densities, many-body Auger recombination will contribute 2.
What drives charge carrier recombination under low-level illumination?
Under low-level illumination, monomolecular (Shockley–Read–Hall 18) processes mediated by trap sites such as elemental vacancies, substitutions or interstitials 19 will dominate charge-carrier recombination.