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# Barabash Rozaliya <barabashr@ornl.gov>
# requesting 8 days, at minimum=6 days
# beamline 34ID-E, Spacially resolved characterization of lattice rotations, crystallographic tilt and strain tensot in GaN layers
# instrument 34ID-E microbeam
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# top:/home/www/beamtime-requests/req00724.txt
# UNICAT Member Beam Time Request  #724
# created Mon Dec 06 18:54:43 CST 2004
####################################################

apsrun:
	2004-03

beamline:
	34ID-E

collaboration:
	Yes

collaborator_Wenjun:
	ON

contact:
	barabashr@ornl.gov

days:
	8

description:
	Quality of GaN layers determines their properties for the production of blue lasers.  GaNis typically grown on substrates like sappire, SiC and Si(111) which exhibit a large difference in lattice constants and thermal expansion coefficients compared to GaN. This leads to a high density of threding dislocations for GaN based layers in the range from 10^10 cm-2. Pendeo  and cantilever epitaxy are promising techniques to overcome this problem and to reduce dislocation density in GaN layers. The laterally growing wing regions of these structures commonly have a different crystallographic orientation relative to the seed region. This so called "wing tilt" results in the formation of dislocation arrays at the interface when adjecent wings coalesce.The minimize the wing tilt we need to characterize local defect structure for different growth modes of GaN.

equipment_required:
	

experiment:
	Spacially resolved characterization of lattice rotations, crystallographic tilt and strain tensot in GaN layers

foreign_nationals:
	Barabash Rozaliya (already has an APS badge)

hazards:
	No hazards are associated with this experiment

instrument:
	34ID-E microbeam

instrument_other:
	

minimumdays:
	6

name:
	Barabash Rozaliya

new_request:
	ON

nonmembers:
	None

unacceptable_dates:
	February 12-20
March 19-April 3

z34ID_change_undulator:
	yes

z34ID_details:
	Energy dispersive measurements are needed

z34ID_on_axis:
	yes

z34ID_parasitic:
	no

z34ID_taper:
	yes


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