非表示:
キーワード:
quantum dot; wetting layer; photoreflectance; photoluminescence
要旨:
The optical transitions of the wetting layers in two-fold self-
assembled InAs/GaAs quantum dot samples are studied as a
function of GaAs spacer thickness by various methods. The
absorption related studies by photoreflectance and selective
photoluminescence excitation spectroscopy reveal already for
thick barriers, for which coupling effects can be excluded, two
energetically separated heavy-hole transitions. This splitting
indicates the formation of two wetting layers during growth
with a 10% difference in width and reflects strain field
interaction between the island layers. Thin spacer layer
samples show in addition the expected wetting layer coupling as
confirmed by subband calculations. (C) 2002 Elsevier Science
B.V. All rights reserved.
