Optical properties of copper-related centres in InP

Abstract

A new Cu-related photoluminescence band in InP is reported. It consists of a sharp zero-phonon line at 1.2889 eV with sharp LO and 'gap mode' local phonon replicas to lower energy superimposed on a broad vibronic background. Zeeman studies show that the recombination process arises from an exciton bound to a neutral isoelectronic centre. Electron and hole g-values of 1.27 and 2.12 respectively are deduced, with both electron and hole having spin 1/2. The very strong diamagnetic shift of the spectrum is found to be equal to that of a shallow donor electron in InP. This demonstrates clearly that the hole is tightly bound in the short-range potential of the centre with binding energy EB h=127.5 meV and that the electron is then weakly bound in the Coulomb field of the hole (EB e=7.3 meV), so that the overall behaviour is of an isoelectronic donor. The thermal activation energy of the vibronic sideband of the luminescence is found to be 135+or-10 meV, in good agreement with the spectroscopic value of the hole binding energy.

Cu3-xP Nanocrystals as a Material Platform for Near-Infrared Plasmonics and Cation Exchange Reactions

“…The formation of Cu 3- x P/InP NC heterostructures is well supported by the experimental evidence that in the bulk there are no known stable Cu–In–P alloys, and even if Cu is a typical dopant for InP, 44 , 46 attempts to diffuse Cu into bulk InP above doping levels (typically smaller than 5 × 10 15 cm –3 ) resulted in the formation of Cu–In metallic precipitates in InP. 46 − 48 …”

“…It is known that Cu + ions can rapidly diffuse in bulk InP (both bulk and nanocrystalline) through interstitial sites 46 allowing for Cu doping of InP NCs even at very low temperatures (i.e., 50 °C). 49 On the other hand, it is not clear whether In 3+ diffusion in Cu 3- x P proceeds likewise interstitially or it is instead dominated by Cu vacancy diffusion.…”

Optical and Morphological Properties of Single-Phased and Dual-Emissive InP/ZnS Quantum Dots via Transition Metallic and Inorganic Ions

“…3 Since the radius of Cu 2+ (0.72 Å) is smaller than that of In 3+ (0.81 Å), the incorporation of copper could be easily realized through interstitial doping into the host materials with low concentration, as suggested in previous work. 22,23 Besides, Mn 2+ (0.80 Å) is about the same size as In 3+ , so it can be supposed that Mn ions tend to reside in substitutional indium sites in the host materials. 24 Apart from this, the difference in successful dopant concentration might also be assigned to different precursor reactivities.…”

Unraveling the Impurity Location and Binding in Heavily Doped Semiconductor Nanocrystals: The Case of Cu in InAs Nanocrystals

“…The use of impurities (or dopants) is a ubiquitous approach for controlling the physical properties of bulk semiconductors and is the basis for their widespread application in electronic and electro-optic components . In light of this, doping, the process of intentional insertion of impurities, is of great interest for further modification of the behavior of semiconductor NCs. − Early studies of NC doping focused on isovalent impurities, leading to enhancement of optical and magnetic properties. − Further modification of properties would emerge from aliovalent doping; ,,− however, “self-purification” by which the impurity is expelled to the NC surface may become predominant due to less favorable chemical stabilization of the incompatible impurity. − …”