H2Se DOPING OF MOCVD GROWN GaAs AND GaAlAs

L'étude de la croissance des couches épitaxiées de GaAs et GaAlAs par le procédé MOCVD met en évidence une relation superlinéaire entre le dopage type n et la fraction molaire H2Se dans la phase gazeuse. Cet effet superlinéaire est observé à la fois pour les dépôts effectués sous pression atmosphérique et pour ceux obtenus sous pression réduite. L'effet anormal de dopage est comparé au dopage H2S pour lequel une relation linéaire de dopage a été observée. Les mécanismes d'incorporation du dopage sont différents pour le souffre et le sélenium et les divers mécanismes de croissance possibles sont discutés.In the growth of epitaxial layers of GaAs and GaAlAs by the MOCVD process a superlinear relationship between the n-type doping and the H2Se mole fraction in the gas phase has been found. This superlinear effect has been observed both with atmospheric and reduced pressure depositions. The anomalous doping effect is compared to H2S doping where a linear doping relationship has been observed. The dopant incorporation mechanism for sulphur and selenium are different and the possible growth mechanisms are discussed

Impurity induced disordering in InGaAs/InGaAlAs quantum wells using implanted fluorine and boron

Impurity induced disordering of an InGaAs/InGaAlAs quantum well structure has been investigated using boron and fluorine. The impurities were introduced by ion implantation and followed by thermal annealing. Small blue shifts in the exciton peak were observed in the boron implanted material. Much larger blue shifts, over 40 meV, were observed in the fluorine implanted material. At annealing temperatures greater than 650 degrees C, red shifts in the exciton peak of unimplanted material were measured

Impurity induced disordering of GaInAs quantum wells with barriers of AlGaInAs or of GaInAsP

Impurity induced disordering of GaInAs quantum well structures with barriers of AlGaInAs and of GaInAsP has been investigated using boron and fluorine. The impurities were introduced by ion implantation followed by thermal annealing. Annealing unimplanted P-based quaternary material at temperatures greater than 500° C caused a blue shift of the exciton peak. At annealing temperatures greater than 650° C red shifts in the exciton peak of unimplanted Al-based quaternary material were observed. Boron implantation caused small blue shifts of the exciton peak in both material systems at low annealing temperatures. Much larger blue shifts were observed in the fluorine implanted samples

Optical tools for intermixing diagnostic: application to InGaAs/InGaAsP microstructures

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Layer selective disordering by photoabsorption-induced thermal diffusion in InGaAs/InP based multiquantum well structures

Laser-induced intermixing of a buried InGaAs/InGaAsP multiquantum well structure using a CW Nd:YAG laser, operating at a wavelength of 1064 nm, has been demonstrated. The process does not involve transient melting of the semiconductor, but relies on preferential absorption by the active region producing sufficient heat to cause intermixing between the wells and barriers. Photoluminescence measurements at 77 K indicate that bandgap shifts as large as 123 meV are obtainable using moderate laser beam power densities and periods of irradiation

Non-destructive approaches to interdiffusion phenomena across GaInAs/GaInAsP interfaces: photoluminescence vs. Raman

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