Accession Number : ADA258814
Title : Excitation and De-Excitation Mechanisms of Er-Doped GaAs and A1GaAs.
Descriptive Note : Doctoral thesis,
Corporate Author : AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
Personal Author(s) : Elsaesser, David W
Report Date : Dec 1992
Pagination or Media Count : 245
Abstract : Electrical and optical characterization have been performed on GaAs and AlxGa1-xAs samples doped with Er either by ion implantation or during Molecular Beam Epitaxial (MBE) growth. Deep Level Transient Spectroscopy (DLTS) and Temperature-Dependent Hall Effect (TDH) measurements indicated the presence of two hole traps in Er-doped GaAs, at 35 and 360 meV above the valence band maximum. The former (shallower) center was thought to be due to Er substituting for a Ga atom (ErGa) and giving rise to an isoelectronic impurity potential. The second center was attributed to an Er atom occupying an interstitial position (Er(i)). Annealing studies performed on Er-implanted GaAs indicated that the ErGa center preferentially formed at higher annealing temperatures ( 850 deg C), with the Er(i) reaching a maximum concentration at an annealing temperature of around 750 deg C. Optical characterization performed by Photoluminescence (PL) measurements showed that the Er(i) center gave a much stronger Er-related intra-4f shell emission. Mechanisms for the excitation of the 4f shells of these two centers are discussed. Similar optically active Eri centers may be forming in AlGaAs.
Descriptors : *EXCITATION , *GALLIUM ARSENIDES , *ALUMINUM GALLIUM ARSENIDES , *ERBIUM , TRANSIENTS , EMISSION , IONS , MEASUREMENT , THESES , ATOMS , DOPING , VALENCE , VALENCE BANDS , MOLECULAR BEAMS , ION IMPLANTATION , INTERSTITIAL , IMPURITIES , ELECTRICAL PROPERTIES , SEMICONDUCTORS , TRAPS , IMPLANTATION , LUMINESCENCE , EPITAXIAL GROWTH , PHOTOLUMINESCENCE , HALL EFFECT , OPTICAL PROPERTIES , TEMPERATURE , ANNEALING , SPECTROSCOPY
Subject Categories : Inorganic Chemistry
Electrical and Electronic Equipment
Solid State Physics
Distribution Statement : APPROVED FOR PUBLIC RELEASE