Excitation and de-excitation mechanisms of Er-doped GaAs and AlGaAs

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1992

OSTI ID:7165461

Elsaesser, D W

Electrical and optical characterization have been performed on GaAs and Al[sub x]Ga[sub 1[minus]x]As samples doped with Er either by ion implantation and during Molecular Beam Epitaxial (MBE) growth. The electrical techniques of Deep Level Transient Spectroscopy (DLTS) and Temperature Dependent Hall Effect (TDH) indicated that Er primarily formed two electrically active centers in both materials. The first center gave rise to a hole trap at E[sub v] + 35 meV, which was thought to be due to Er substituting for a Ga atom (Er[sub Ga]) and giving rise to an isoelectronic impurity potential. The second center also gave rise to a hole trap at approximately E[sub v] + 360 meV, and was attributed to an Er atom occupying an interstitial position (Er[sub i]). Annealing studies performed on Er-implanted GaAs indicated that the Er[sub Ga] center preferentially formed at higher annealing temperatures (> 850[degrees]C), with the Er[sub i] reaching a maximum concentration at an annealing temperature of around 750[degrees]C. Optical characterization performed by Photoluminescence (PL) measurements showed that the Er[sub i] center gave much stronger Er-related emissions due to the transition [sup 4]I[sub 13/2] [yields] [sup 4]I[sub 15/2] in the unfilled Er[sup 3+]-4f shell than was observed for 4f-emissions associated with the Er[sub Ga] center. Mechanisms for the excitation and de-excitation of the Er-4f shell in GaAs were proposed. DLTS measurements also detected the presence of a large concentration of Ga-antisite (Ga[sub As]) defects as well as As-interstitial (As[sub i]) defects. Two other likely Er-centers were proposed, Er[sub Ga]-Ga[sub As] and Er[sub Ga]-As[sub i]. Electrical and optical characterization of Er-doped MBE-grown Al[sub 0.5]Ga[sub 0.5]As indicated that the solubility limit of Er in this material was possibly as high as 2 [times] 10[sup 19] cm[sup [minus]3], as compared to 7 [times] 10[sup 17] cm[sup [minus]3] in GaAs.

• Research Organization: Air Force Inst. of Tech., Wright-Patterson AFB, OH (United States)
• OSTI ID: 7165461
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360606* -- Other Materials-- Physical Properties-- (1992-)
665000 -- Physics of Condensed Matter-- (1992-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALUMINIUM ARSENIDES
ALUMINIUM COMPOUNDS
ARSENIC COMPOUNDS
ARSENIDES
CHARGED PARTICLES
DE-EXCITATION
DEEP LEVEL TRANSIENT SPECTROSCOPY
DOPED MATERIALS
ELECTRICAL PROPERTIES
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
ERBIUM IONS
EXCITATION
F STATES
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
HALL EFFECT
IONS
LUMINESCENCE
MATERIALS
OPTICAL PROPERTIES
PHOTOLUMINESCENCE
PHYSICAL PROPERTIES
PNICTIDES
SPECTROSCOPY