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I � Motivation
letter
Dear President
I am writing to seek for a postdoctoral
research in your laboratory or university. I am able to
create by the Double Step technique a growing of GaN
(Gallium nitride) by MOCVD (Metal Organic Chemical Vapor
Deposit) or MOVPE (Metal Organic Vapor Phase Epitaxy), and
to characterize by different techniques: X-Ray Diffraction,
Photoluminescence, Reflectivity, mobility by Hall Effect,
MEB (Microcopy Electron Beam)...
I carried out my doctoral work, on Double Step
growing GaN by MOCVD with Dr O.Briot, my doctoral work
Director, in the professor R.L. Aulombard's Laboratory, in
Montpellier and optics characterization with Doctor and CNRS
researcher�s: B.Gil.
During my research, my Director of research and I
have been involved in three conferences about GaN
semiconductor III-V:
USA : MRS FALL MEETING,
Boston (Nov 27 - Dec 1, 1995)
Europe : First
European GaN Workshop (EGW-1) RIGI, Switzerland (June 2-4,
1996)
Europe : E-MRS 1996
Spring Meeting, Strasbourg, (June 4-7, 1996)
The particularity of my work has been the GaN growing
by low-pressure (76 Torr) MOCVD by Double Step techniques on
GaN and AlN buffer, on sapphire substrate. We have obtained
some characteristics epilayers GaN as Nakamura epilayers.
And moreover the optimization GaN epilayers has allowed
obtaining one of first result in the world: Presence of
exciton A in the photoluminescence at 2 K accurate by the
reflectivity (in GaN/buffer GaN/sapphire).
During my first doctoral year, I have obtained
some extensive experience too in ZnCdSe epilayers MOCVD
growing and some realizations GRIN-SCHs structure based
ZnSe\ZnCdSe.
I am very interested about device realization
based GaInAlN (blue LED, LD, transistors..).
I believe that working with you and your
colleagues would provide a good opportunity to shared our
knowledge and strengthen my skills.
Enclosed my resume, however if you need any
information concerning my publications (in English) and my
thesis (in French) please contact me (by : phone, letter,
E-mail).
Thank you for your time and consideration, I hope my
skills will interest you and look forward to hear from you
soon.
References : My Research Director:
Doctor and CNRS researcher : O.BRIOT
Optics characterization: Doctor and CNRS research
Director : B.GIL.
LABORATOIRE D�EPITAXIE DES
MATERIAUX III-V
Groupe d�Etude des Semiconducteurs
Université Montpellier II
34095 MONTPELLIER CEDEX 5
FRANCE
E.Mail : Research Director:
[email protected]. fr
Optics characterization: [email protected].
fr
Upon request publications on my work
Yours sincerely Jean-Paul ALEXIS Ph.D.
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II - C.V.
- Doctor in the
semiconductor science
-
- Thesis in
: Epitaxy by MOVPE (MOCVD)
Double
Step techniques and
characterization of semiconductor III-V, GaN (Gallium
Nitride) on GaN and AlN (Aluminum Nitride) buffer, on
sapphire substrate.
Formation : Dense environment and materials, Electronics
materials and the ionic of solid
EDUCATION &
WORK HYSTORY:
1994-1997
Doctoral research in semiconductor science to
create by the Double Step technique a growing of GaN
(Gallium nitride) the semiconductor III-V, by MOCVD (Metal
Organic Chemical Vapor Deposit) or MOVPE (Metal Organic
Vapor Phase Epitaxy), and to characterize by different
techniques : X-Ray diffraction, Photoluminescence,
Reflectivity, mobility by Hall Effect, MEB (Microscopy
Electron Beam)...
Results : Characteristics epilayers GaN as
Nakamura epilayers and one of the first result in the world
: Presence of exciton A in the photoluminescence at 2 K
accurate by the reflectivity (in GaN/buffer
GaN/sapphire).
Thesis : Growing of GaN by MOVPE, at the
Laboratory "Laboratoire d�Epitaxie des matériaux
III-V", GES, Université de MONTPELLIER II �
France.
Note : During 1994-1995 - Beginning on the
thesis : Growing semiconductor II-VI, ZnCdSe by MOVPE.
1993-1994
MBS Instrumentation and Physic Measure at BORDEAUX
I, university � France.
1991-1993
MBS in Electronic Electro-mechanic and Automatic
at BORDEAUX I university - FRANCE
1990-1991
Associate Degree in Electronic Technology, Systems
Industry of Computers Science University of Technology of
MONTPELLIER � France � came out First
graduate.
Internships : Study of making low noise
device converter SHF in MATTHELEC society, in the
Montpellier region - FRANCE, study-internships (2 months) in
1991, graduate by Diploma University of Technology
Electronic and Systems Industry Computers.
1990-1988
Associate Degree High School Diploma Certificate
Technician Superior Electronic. Internships :
Maintenance and restoring, medical equipment, and systems
automatic control door in TAS society, Z.I. of Jarry
GUADELOUPE region, (2 months) in 1990, graduate by the High
School Diploma Certificate Technician Superior
Electronic.
1987-1988
High School Diploma in Electronic.
PERSONAL:
Age : 29.
Nationality : French.
Languages : English : write and speak / medium
level.
Sport : Basket-Ball, excursion, Jogging, Bicycle;
Excellent health.
Computers :
- Software and systems : Windows 95, Windows, NT4,
LINUX, MATLAB, MAPLE, LABVIEW, ORIGIN, MSoffice,
NETSCAPE, EUDORA- HTML page creation.
- Skills in computers
systems maintenance and operating systems.
- Others : Game chess, Electronics realization,
joinery, photography.
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III - My Publication List
Linear and nonlinear optical properties of ZnSe and
ZnS thin epitaxial layers and of CdZnSe/ZnSe quantum
wells.
Book : Semiconductor Heteroepitaxy Growth,
Characterization and Device Application.
Montpellier 4 -7 July 1995. Editors, B.Gil,
R.L.Aulombard
Authors: P.Gilliot, A.Chergui, I.Pelant, J.Valenta,
R.Tomasiumas, and B.Honerlage,N.Briot, O.Briot, B.Gil,
J.P.Alexis.
Optical properties and recombination processes in
(Zn,Cd)Se Graded Index Separate Confinement
Heterostrutures.
Revue: Superlattices and Microstructures, Vol. 17,
No4, 1995.
Authors: L.Aigouy, J.P.Alexis, O.Briot, T.Cloitre, B.Gil,
R.L.Aulombard and M.Averous.
Strain effects in GaN on sapphire: Towards a
quantitative comprehension
Conference : MRS Fall Meeting, Boston USA November
1995
Authors : O.Briot, , J.P.Alexis, B.Gil, R.L.Aulombard
Growth kinetics and structural quality in GaN epitaxy
by low pressure MOVPE
Conference : MRS Fall Meeting, Boston USA November
1995
Authors : O.Briot, , J.P.Alexis, B.Gil, R.L.Aulombard
Optimization and optical studies of ZnCdSe-ZnSe
heterostrusture grown by MOVPE
Revue: Journal of Crystal Growth 159,(1996)
438-442
Authors: T.Cloitre, L.Aigouy, B.Gil, O.Briot, N.Briot,
J.P.Alexis, R.L.Aulombard
Optical properties of GaN epilayers on
sapphire
Revue: Journal of Applied Physics Vol. 80, No 9, 1
November 1996
Authors: M.Tchounkeu, O.Briot, B.Gil, J.P.Alexis,
R.L.Aulombard
Optimization of the MOVPE grown of GaN on
sapphire
Revue: Materials Science and Engineering B 1996
Authors: O.Briot, J.P.Alexis, M.Tchounkeu, R.L.Aulombard
Influence of the V/III molar ratio on the structural
and electronic properties of MOVPE grown GaN
Revue: Solid-State Electronics 1997
Authors: O.Briot, J.P.Alexis, S.Sanchez, B.Gil,
R.L.Aulombard
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IV - Thesis Subject Resume
of my Work Thesis
- Characterization and
Optimization
- of low
pressure MOCVD growth of GaN
- on
sapphire by "Double Step Process"
- using GaN
and AlN Buffer layers
Dr Jean-Paul ALEXIS
GES - Groupe d`Etudes des Semiconducteurs
Universite de MONTPELLIER II
Laboratoire d`Epitaxy
The III-V nitrides have an increasing interest, due to
their potentiel for the realization of new devices (LED, LD,
sensors, FET family etc...). Some devices are already in
production lines, since blue and green LEDs have already
been on the market for a few years.
This work focused on low pressure (76 Torrs) MOCVD
growth of GaN epilayers on sapphire by `Double Step
Process` using GaN and AlN Buffer layers substrate with
ammonia and triethylgallium as precursors.
A wide range of operating conditions have been
investigated: the temperature was varied between 950
oC and 1050 oC and the molar ratio was
changed from 1000 to 10 000.
An attempt will be carried out in order to
understand the growth mechanisms because the growth rate of
GaN epilayers at both low (550 oC) and high
(980oC) growth temperature versus NH3
flow rate. A competitive absorption will be invoked to
explain this behavior and a simple model will be
proposed.
We have optimized the growth conditions by
studying carefully the influence of each parameter of the
growth process by using X-Ray diffraction, reflectivity,
photoluminescence...
A detailed investigation of the optical properties
of GaN epilayers has revealed to us that the modification of
the spectral energies is linked to residual strain
fields.
The magnitude of these residual strains is linked
to growth conditions rather than the thickness of the
epilayers, although it depends.
Because the strain induced a evolution of the
wurtzite valence band, a relation between the positions
excitons (A, B, C) energies and the
biaxial compression will be proposed.
Finally, the best GaN epilayers with a GaN buffer
layer is obtained with a photoluminescence at 2 K dominated
by the free exciton (A exciton).
After the rapid success of the growth of the
epilayers GaN/AlN Buffer/Sapphire substrate, an attempt of
comparison will be carry out on the difference of quality
with the epilayers GaN/GaN Buffer/Sapphire substrate.
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