ISSN:
1432-0630
Keywords:
PACS: 68.55; 78.70
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
Abstract. We have studied MBE grown amorphous silicon, which was recrystallized at different temperatures for one hour, with a pulsed positron beam. A positron lifetime of 538±10 ps in the as-grown state is attributed to microvoids containing at least 10 vacancies. An incompletely recrystallized sample annealed at 500 °C shows an additional long lifetime from ortho-positronium (o-Ps) pick-off annihilation. The o-Ps component disappears for samples, recrystallized at 700 °C and above, and the defect lifetime steadily decreases with higher annealing temperature until a value of 310 ps is reached for the layer annealed at 1200 °C. This value is explained by positron trapping at dislocations or small vacancy defects stabilized by dislocations or impurities.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01538214
