1. Theory

Definition: An MOCVD (OMVPE) reactor grows epitaxial compound semiconductors from metal-organic group III sources and group V hydrides, whose weak metal-organic bonds break thermally at the hot wafer (Georgia Tech; Stringfellow).
Growth regimes: Below about 550 $^{\circ}$ C growth of GaAs from TMGa is limited by surface kinetics; from about 550 to 800 $^{\circ}$ C it is diffusion-limited and nearly temperature independent (Stringfellow).
Group III control: In the diffusion-limited regime the growth rate is proportional to the group III partial pressure, and at V/III much greater than 1 all arriving group III is incorporated (Stringfellow).
Epitaxy: The layer copies the substrate crystal and must be lattice matched to avoid dislocations (Georgia Tech).

2. Working Principle

Precursors: TMGa with arsine for GaAs, or with NH $_{3}$ for GaN, in H $_{2}$ or N $_{2}$ carrier gas (Stringfellow; Lansheng et al.; Czernecki et al.).
Reactor: A close-coupled showerhead over a heated graphite susceptor, 3 x 2 inch, at about 150 mbar (Czernecki et al.).
GaN conditions: About 950 to 1000 $^{\circ}$ C with V/III near 2000 (Czernecki et al.; Lansheng et al.).
Monitoring: 635 nm laser reflectometry in situ (Czernecki et al.).

3. Applications

Optoelectronics: InGaN LEDs and low-cost optical III-V devices (Georgia Tech; Quantum Well LED (InGaN-GaN and AlGaInP) page).
Heterostructure transistors: GaAs MODFETs and GaN layers (Georgia Tech).
Characterisation: Layers checked by HRXRD and photoluminescence (my reading).

Chemistry and Growth Regimes

Name	Formula	Related Formulae	Variables/Constants
Overall reaction	$(C H_{3})_{3} G a (v) + A s H_{3} (v) \to G a A s (s) + 3 C H_{4}$	$(C H_{3})_{3} G a + N H_{3} \to G a N (s) + 3 C H_{4}$	$S t r in g f e l l o w : T M G a an d a r s in e a s t h e main e x am pl e; L an s h e n g e t a l . : T M G a an d N H_{3} in H_{2}; G eor g ia T ec h : w e ak m e t a l - or g ani c b o n d b r o k e n t h er ma l l y a t t h e w a f er, or g ani cs p u m p e d a w a y$ $(co m p u t e d : t h e m e t han e b y - p r o d u c t ba l an ces C an d H in b o t h e q u a t i o n s)$
Diffusion-limited growth	$G \propto p_{I I I}$	$T \approx 550 to 800^{\circ} C (GaAs)$	$G : g r o w t h r a t e$ $p_{I I I} : g r o u p I I I p a r t ia l p r ess u r e; S t r in g f e l l o w : n e a r l y t e m p er a t u r e in d e p e n d e n t, t h e n or ma l O M V P E r e g im e, a l l a r r i v in g g r o u p I I I in cor p or a t e d a t V / I I I m u c h g r e a t er t han 1$ $(m y r e a d in g : t h e g r o u p I I I f l o w co n t r o l l er i s t h e g r o w t h - r a t e k n o b)$
Kinetic regime	$G \propto exp (- \frac{E _{a}}{k _{B} T})$	$T < 550^{\circ} C (TMGa)$	$S t r in g f e l l o w : r a t e r i s in g e x p o n e n t ia l l y w i t h t e m p er a t u r e, t h r es h o l d d e p e n d in g o n t h e g r o u p I I I p r ec u r sor$ $(m y r e a d in g : t h e p r ec u r so r^{'} s d eco m p os i t i o n k in e t i cs se t s w h er e t hi s r e g im e e n d s)$

V/III, Temperature and Carrier Gas

Name	Formula	Related Formulae	Variables/Constants
V/III ratio	$\frac{V}{I I I} = \frac{F _{V}}{F _{I I I}}$	$\frac{V}{I I I} = 2 (G a A s example), 2000 (G a N)$	$F : in p u t m o l a r f l o w s; S t r in g f e l l o w : d e f ini t i o n an d e x am pl e; L an s h e n g e t a l . : G a N s im u l a t i o n a t 40 Torr$ $(co m p u t e d : G a N u ses 1000 t im es t h e V / I I I o f t h e G a A s e x am pl e)$
GaN temperature	$T_{o pt} \approx 1000^{\circ} C$	$T_{t y p i c a l} = 950^{\circ} C (thermocouple below susceptor)$	$L an s h e n g e t a l . : p y r o l y s i s s t r e n g t h e nin g w i t h t e m p er a t u r e, r a t e r i s in g b e l o w 1000^{\circ} C, H_{2} e t c hin g ab o v e ab o u t 800^{\circ} C; C z er n ec k i e t a l . : 770 t o 1030^{\circ} C a t 150 mbar, 1140^{\circ} C se tp o in t f or s u r f a ce m e a s u r e m e n t s$ $(m y r e a d in g : t h e q u o t e d t e m p er a t u r e d e p e n d s o n w h er e i t i s m e a s u r e d)$
Carrier gas	$G_{H_{2}} \approx 1.2 G_{N_{2}}$	$GAP = 5 to 25 mm$	$C z er n ec k i e t a l . : a t 950^{\circ} C f or s h o w er h e a d g a p s b e l o w 18 mm, 8 slm t o t a l f l o w, 3 \times 2 in c h c l ose - co u pl e d s h o w er h e a d$ $(m y r e a d in g : c a r r i er g a s c han g es t r an s p or t a s w e l l a s s u r f a ce e t c hin g)$

Epitaxial Quality

Name	Formula	Related Formulae	Variables/Constants
Lattice match	$a_{f i l m} \approx a_{s u b s t r a t e}$	$mismatch \Rightarrow dislocations$	$G eor g ia T ec h : b o n d s c ann o t s t r e t c h e n o ug h; G a N / G a_{0.75} I n_{0.25} N / G a N L E D an d G a A s M O D F E T e x am pl es; X - R a y D i f f r a c t o m e t er (X R D an d H R X R D) p a g e$ $(m y r e a d in g : H R X R D i s t h e s t an d a r d c h ec k o f s t r ain an d co m p os i t i o n in s u c h l a y er s)$
Carbon and hydrogen	$[C] ↓ > 100 \times with Sb surfactant (GaP)$	$[Z n] ↑ 60 % at S b / I I I = 0.012 (G a A s)$	$S t r in g f e l l o w : s u r f a c t an t e f f ec t s; G eor g ia T ec h : c a r b o n an d u nin t e n t i o na l h y d r o g e n so m e t im es a p r o b l e m$ $(m y r e a d in g : c a r b o n co m es f r o m t h e m e t h y l l i g an d s o f t h e p r ec u r sor s)$
In-situ monitoring	$λ_{r e f l} = 635 nm$	$growth rate from reflectance$	$C z er n ec k i e t a l . : l a ser r e f l ec t o m e t r y d u r in g G a N g r o w t h; P h o t o l u min esce n ce S p ec t r o m e t er p a g e f or e x - s i t u o pt i c a l c h ec k s$ $(m y r e a d in g : in t er f er e n ce osc i l l a t i o n s in r e f l ec t an ce t r a c k t hi c k n ess d u r in g g r o w t h)$

Important Questions

Ques: How does an MOCVD reactor grow compound semiconductors?

By decomposing metal-organic and hydride precursors on a hot crystalline substrate. Georgia Tech explains that metals with very low vapour pressure are attached to organic groups so they can be carried as gases, and that the weak metal-organic bond breaks thermally at the wafer while the organic by-product is pumped away. Stringfellow uses GaAs from trimethylgallium and arsine, $(C H_{3})_{3} G a + A s H_{3} \to G a A s$ , as the main example; methane balances the equation (computed). Lansheng et al. model GaN from TMGa and NH $_{3}$ in hydrogen. Georgia Tech notes that MOCVD dominates low-cost optical III-V technology and that metal-organics are highly hazardous because the body absorbs them readily. The epitaxial layer must be lattice matched to avoid dislocations (Georgia Tech). Reference: W. A. Doolittle, ECE 6450 Lectures 13 and 14 ‘CVD and Epitaxy’, Georgia Institute of Technology: MOCVD mainly for II-VI and III-V semiconductors, special oxides and metals, low-vapour-pressure metals carried as metal-organics whose weak bond breaks thermally at the wafer, carbon and unintentional hydrogen incorporation sometimes a problem, metal-organics readily absorbed by the body and highly hazardous, MOCVD dominating low-cost optical III-V technology, epitaxy needing lattice match to avoid dislocations, GaN/Ga0.75In0.25N/GaN LED and GaAs MODFET examples, MBE for highest purity and III-V electronics (fetch-tool summary); G. B. Stringfellow, ‘Fundamentals of vapor phase epitaxial growth processes’, AIP Conference Proceedings CP916, Perspectives on Inorganic, Organic, and Biological Crystal Growth (2007): GaAs from TMGa and arsine, (CH3)3Ga + AsH3 -> GaAs, diffusion-limited growth from about 550 to 800 C nearly independent of temperature as the normal situation, surface-kinetic growth below about 550 C rising exponentially with temperature with the threshold depending on the group III precursor, growth rate proportional to Ga partial pressure, V/III defined as input group V over group III molar flow with an example of 2.0, Ga nearly depleted at the interface at V/III much greater than 1, Sb surfactant cutting background carbon in GaP below SIMS detection and by more than 100 times, raising Zn incorporation in GaAs by 60 per cent at Sb/III = 0.012 and in GaP up to 10 times, other precursors TESb, TEAs, phosphine, TBP and DMHy (fetch-tool summary); Feng Lansheng, Guo Runqiu and Zhang Jincheng (Xidian University), ‘The effect of substrate temperature on chemical reactions during GaN growth in a vertical MOCVD’, ICMMITA 2016, Advances in Computer Science Research vol. 71: simulation of TMGa + NH3 in H2 at 40 torr, V/III 2000, inlet 0.3 m/s, adduct reactions falling and pyrolysis strengthening with temperature, growth rate rising with temperature below 1000 C, hydrogen etching of GaN significant above about 800 C and notable above 1000 C, optimum substrate temperature about 1000 C, simulated rate distribution agreeing roughly with experiment (fetch-tool summary).

Ques: What sets the growth rate in MOCVD?

Usually the group III supply. Stringfellow finds that GaAs growth from TMGa is diffusion-limited from about 550 to 800 $^{\circ} C$ , nearly independent of temperature, and calls this the normal situation. There the growth rate is proportional to the Ga partial pressure, and at V/III much greater than 1 the Ga is nearly depleted at the interface, so essentially all arriving group III is incorporated. Below about 550 $^{\circ} C$ growth becomes surface-kinetically limited and rises exponentially with temperature, with a threshold that depends on the group III precursor. In my reading, the group III mass-flow controller is therefore the growth-rate knob. Temperature mainly sets crystal quality and incorporation rather than thickness. Reference: G. B. Stringfellow, ‘Fundamentals of vapor phase epitaxial growth processes’, AIP Conference Proceedings CP916, Perspectives on Inorganic, Organic, and Biological Crystal Growth (2007): GaAs from TMGa and arsine, (CH3)3Ga + AsH3 -> GaAs, diffusion-limited growth from about 550 to 800 C nearly independent of temperature as the normal situation, surface-kinetic growth below about 550 C rising exponentially with temperature with the threshold depending on the group III precursor, growth rate proportional to Ga partial pressure, V/III defined as input group V over group III molar flow with an example of 2.0, Ga nearly depleted at the interface at V/III much greater than 1, Sb surfactant cutting background carbon in GaP below SIMS detection and by more than 100 times, raising Zn incorporation in GaAs by 60 per cent at Sb/III = 0.012 and in GaP up to 10 times, other precursors TESb, TEAs, phosphine, TBP and DMHy (fetch-tool summary).

Ques: Why does GaN need a much higher V/III ratio than GaAs?

Because the group V source must be supplied in large excess. Stringfellow defines V/III as the input group V to group III molar flow ratio and uses 2.0 in a GaAs example. Lansheng et al. simulate GaN at V/III of 2000, 40 $Torr$ and an inlet velocity of 0.3 $m/s$ , 1000 times higher (computed). Czernecki et al. vary V/III through the NH $_{3}$ flow at a constant 8 $slm$ total. Georgia Tech notes that GaN chemistry must make Ga bond to N rather than to Ga, with antisite defects at about parts-per-trillion levels. The opened sources do not state why the excess is needed. In my reading, it implies that only a small fraction of the NH $_{3}$ delivers active nitrogen to the surface, so the rest must be supplied in surplus. Reference: G. B. Stringfellow, ‘Fundamentals of vapor phase epitaxial growth processes’, AIP Conference Proceedings CP916, Perspectives on Inorganic, Organic, and Biological Crystal Growth (2007): GaAs from TMGa and arsine, (CH3)3Ga + AsH3 -> GaAs, diffusion-limited growth from about 550 to 800 C nearly independent of temperature as the normal situation, surface-kinetic growth below about 550 C rising exponentially with temperature with the threshold depending on the group III precursor, growth rate proportional to Ga partial pressure, V/III defined as input group V over group III molar flow with an example of 2.0, Ga nearly depleted at the interface at V/III much greater than 1, Sb surfactant cutting background carbon in GaP below SIMS detection and by more than 100 times, raising Zn incorporation in GaAs by 60 per cent at Sb/III = 0.012 and in GaP up to 10 times, other precursors TESb, TEAs, phosphine, TBP and DMHy (fetch-tool summary); Feng Lansheng, Guo Runqiu and Zhang Jincheng (Xidian University), ‘The effect of substrate temperature on chemical reactions during GaN growth in a vertical MOCVD’, ICMMITA 2016, Advances in Computer Science Research vol. 71: simulation of TMGa + NH3 in H2 at 40 torr, V/III 2000, inlet 0.3 m/s, adduct reactions falling and pyrolysis strengthening with temperature, growth rate rising with temperature below 1000 C, hydrogen etching of GaN significant above about 800 C and notable above 1000 C, optimum substrate temperature about 1000 C, simulated rate distribution agreeing roughly with experiment (fetch-tool summary); R. Czernecki, K. Moszak, W. Olszewski, E. Grzanka and M. Leszczynski, ‘Influence of showerhead-sample distance (GAP) in MOVPE close coupled showerhead reactor on GaN growth’, Materials 12, 3375 (2019): AIXTRON CCS 3 x 2 inch reactor, GAP 5 to 25 mm (default 11 mm), TMGa and NH3 in H2 or N2 at 8 slm total, 150 mbar for the temperature study, 770, 950 (typical) and 1030 C measured by a thermocouple below the graphite susceptor, 1140 C setpoint for surface-temperature measurements, H2 growth rate about 20 per cent above N2 at 950 C for GAP below 18 mm, 635 nm laser reflectometry, V/III varied by NH3 flow (fetch-tool summary); W. A. Doolittle, ECE 6450 Lectures 13 and 14 ‘CVD and Epitaxy’, Georgia Institute of Technology: MOCVD mainly for II-VI and III-V semiconductors, special oxides and metals, low-vapour-pressure metals carried as metal-organics whose weak bond breaks thermally at the wafer, carbon and unintentional hydrogen incorporation sometimes a problem, metal-organics readily absorbed by the body and highly hazardous, MOCVD dominating low-cost optical III-V technology, epitaxy needing lattice match to avoid dislocations, GaN/Ga0.75In0.25N/GaN LED and GaAs MODFET examples, MBE for highest purity and III-V electronics (fetch-tool summary).

Ques: What temperature is GaN grown at, and which figure is more likely?

About 1000 $^{\circ} C$ at the surface; the 950 $^{\circ} C$ figure is a thermocouple reading. Lansheng et al. find from simulation that pyrolysis strengthens and the growth rate rises with temperature up to about 1000 $^{\circ} C$ , which they call optimal. Hydrogen etching of GaN becomes significant above about 800 $^{\circ} C$ . Czernecki et al. call 950 $^{\circ} C$ typical, but measure it with a thermocouple below the graphite susceptor, and quote a 1140 $^{\circ} C$ setpoint for their surface-temperature measurements. In my reading, the two figures describe different points in the stack and need not conflict. The Lansheng value refers to the substrate and is more likely the true growth-surface temperature. Every MOCVD temperature should state where it was measured (my reading). Reference: Feng Lansheng, Guo Runqiu and Zhang Jincheng (Xidian University), ‘The effect of substrate temperature on chemical reactions during GaN growth in a vertical MOCVD’, ICMMITA 2016, Advances in Computer Science Research vol. 71: simulation of TMGa + NH3 in H2 at 40 torr, V/III 2000, inlet 0.3 m/s, adduct reactions falling and pyrolysis strengthening with temperature, growth rate rising with temperature below 1000 C, hydrogen etching of GaN significant above about 800 C and notable above 1000 C, optimum substrate temperature about 1000 C, simulated rate distribution agreeing roughly with experiment (fetch-tool summary); R. Czernecki, K. Moszak, W. Olszewski, E. Grzanka and M. Leszczynski, ‘Influence of showerhead-sample distance (GAP) in MOVPE close coupled showerhead reactor on GaN growth’, Materials 12, 3375 (2019): AIXTRON CCS 3 x 2 inch reactor, GAP 5 to 25 mm (default 11 mm), TMGa and NH3 in H2 or N2 at 8 slm total, 150 mbar for the temperature study, 770, 950 (typical) and 1030 C measured by a thermocouple below the graphite susceptor, 1140 C setpoint for surface-temperature measurements, H2 growth rate about 20 per cent above N2 at 950 C for GAP below 18 mm, 635 nm laser reflectometry, V/III varied by NH3 flow (fetch-tool summary).

Ques: How do carrier gas and reactor geometry affect growth?

Through transport to the surface. Czernecki et al. used an AIXTRON close-coupled showerhead reactor with 3 x 2 inch wafers and a showerhead-to-sample gap adjustable from 5 to 25 $mm$ , default 11 $mm$ . At 950 $^{\circ} C$ the growth rate in H $_{2}$ carrier was about 20 per cent higher than in N $_{2}$ for gaps below 18 $mm$ . Lansheng et al., in contrast, predict that hydrogen etches GaN above about 800 $^{\circ} C$ , which would lower the rate. These are not necessarily contradictory: in my reading, the carrier gas changes the transport of TMGa to the surface as well as the etching, and at 950 $^{\circ} C$ the transport gain can dominate. Stringfellow’s diffusion-limited model supports this, since the rate follows transport of the group III species. Reference: R. Czernecki, K. Moszak, W. Olszewski, E. Grzanka and M. Leszczynski, ‘Influence of showerhead-sample distance (GAP) in MOVPE close coupled showerhead reactor on GaN growth’, Materials 12, 3375 (2019): AIXTRON CCS 3 x 2 inch reactor, GAP 5 to 25 mm (default 11 mm), TMGa and NH3 in H2 or N2 at 8 slm total, 150 mbar for the temperature study, 770, 950 (typical) and 1030 C measured by a thermocouple below the graphite susceptor, 1140 C setpoint for surface-temperature measurements, H2 growth rate about 20 per cent above N2 at 950 C for GAP below 18 mm, 635 nm laser reflectometry, V/III varied by NH3 flow (fetch-tool summary); Feng Lansheng, Guo Runqiu and Zhang Jincheng (Xidian University), ‘The effect of substrate temperature on chemical reactions during GaN growth in a vertical MOCVD’, ICMMITA 2016, Advances in Computer Science Research vol. 71: simulation of TMGa + NH3 in H2 at 40 torr, V/III 2000, inlet 0.3 m/s, adduct reactions falling and pyrolysis strengthening with temperature, growth rate rising with temperature below 1000 C, hydrogen etching of GaN significant above about 800 C and notable above 1000 C, optimum substrate temperature about 1000 C, simulated rate distribution agreeing roughly with experiment (fetch-tool summary); G. B. Stringfellow, ‘Fundamentals of vapor phase epitaxial growth processes’, AIP Conference Proceedings CP916, Perspectives on Inorganic, Organic, and Biological Crystal Growth (2007): GaAs from TMGa and arsine, (CH3)3Ga + AsH3 -> GaAs, diffusion-limited growth from about 550 to 800 C nearly independent of temperature as the normal situation, surface-kinetic growth below about 550 C rising exponentially with temperature with the threshold depending on the group III precursor, growth rate proportional to Ga partial pressure, V/III defined as input group V over group III molar flow with an example of 2.0, Ga nearly depleted at the interface at V/III much greater than 1, Sb surfactant cutting background carbon in GaP below SIMS detection and by more than 100 times, raising Zn incorporation in GaAs by 60 per cent at Sb/III = 0.012 and in GaP up to 10 times, other precursors TESb, TEAs, phosphine, TBP and DMHy (fetch-tool summary).

Ques: Where do carbon and other impurities come from, and how are layers checked?

Mainly from the precursors themselves. Georgia Tech notes that carbon contamination and unintentional hydrogen incorporation are sometimes a problem in MOCVD. In my reading the carbon comes from the methyl ligands of sources such as TMGa. Stringfellow reports that adding Sb as a surfactant cut background carbon in GaP below the SIMS detection limit, by more than 100 times in one sample. It also raised Zn incorporation in GaAs by 60 per cent at Sb/III = 0.012. Czernecki et al. monitored growth in situ by 635 $nm$ laser reflectometry. Ex situ, strain and composition are checked as on the X-Ray Diffractometer (XRD and HRXRD) page and emission as on the Photoluminescence Spectrometer page, especially for the LED stacks on the Quantum Well LED page (my reading). Reference: W. A. Doolittle, ECE 6450 Lectures 13 and 14 ‘CVD and Epitaxy’, Georgia Institute of Technology: MOCVD mainly for II-VI and III-V semiconductors, special oxides and metals, low-vapour-pressure metals carried as metal-organics whose weak bond breaks thermally at the wafer, carbon and unintentional hydrogen incorporation sometimes a problem, metal-organics readily absorbed by the body and highly hazardous, MOCVD dominating low-cost optical III-V technology, epitaxy needing lattice match to avoid dislocations, GaN/Ga0.75In0.25N/GaN LED and GaAs MODFET examples, MBE for highest purity and III-V electronics (fetch-tool summary); G. B. Stringfellow, ‘Fundamentals of vapor phase epitaxial growth processes’, AIP Conference Proceedings CP916, Perspectives on Inorganic, Organic, and Biological Crystal Growth (2007): GaAs from TMGa and arsine, (CH3)3Ga + AsH3 -> GaAs, diffusion-limited growth from about 550 to 800 C nearly independent of temperature as the normal situation, surface-kinetic growth below about 550 C rising exponentially with temperature with the threshold depending on the group III precursor, growth rate proportional to Ga partial pressure, V/III defined as input group V over group III molar flow with an example of 2.0, Ga nearly depleted at the interface at V/III much greater than 1, Sb surfactant cutting background carbon in GaP below SIMS detection and by more than 100 times, raising Zn incorporation in GaAs by 60 per cent at Sb/III = 0.012 and in GaP up to 10 times, other precursors TESb, TEAs, phosphine, TBP and DMHy (fetch-tool summary); R. Czernecki, K. Moszak, W. Olszewski, E. Grzanka and M. Leszczynski, ‘Influence of showerhead-sample distance (GAP) in MOVPE close coupled showerhead reactor on GaN growth’, Materials 12, 3375 (2019): AIXTRON CCS 3 x 2 inch reactor, GAP 5 to 25 mm (default 11 mm), TMGa and NH3 in H2 or N2 at 8 slm total, 150 mbar for the temperature study, 770, 950 (typical) and 1030 C measured by a thermocouple below the graphite susceptor, 1140 C setpoint for surface-temperature measurements, H2 growth rate about 20 per cent above N2 at 950 C for GAP below 18 mm, 635 nm laser reflectometry, V/III varied by NH3 flow (fetch-tool summary); X-Ray Diffractometer (XRD and HRXRD) page of this vault; Photoluminescence Spectrometer page of this vault; Quantum Well LED (InGaN-GaN and AlGaInP) page of this vault.

References

G. B. Stringfellow, “Fundamentals of vapor phase epitaxial growth processes,” AIP Conference Proceedings CP916, 2007. Available: https://collections.lib.utah.edu/dl_files/b4/04/b404dc111a8a9725bd80fb776b124dbb568e3cf7.pdf
W. A. Doolittle, “CVD and epitaxy,” ECE 6450 Lectures 13 and 14, Georgia Institute of Technology. Available: https://alan.ece.gatech.edu/ECE6450/Lectures/ECE6450L13and14-CVD%20and%20Epitaxy.pdf
F. Lansheng, G. Runqiu and Z. Jincheng, “The effect of substrate temperature on chemical reactions during GaN growth in a vertical MOCVD,” ICMMITA 2016, Advances in Computer Science Research, vol. 71. Available: https://download.atlantis-press.com/article/25868343.pdf
R. Czernecki, K. Moszak, W. Olszewski, E. Grzanka and M. Leszczynski, “Influence of showerhead-sample distance (GAP) in MOVPE close coupled showerhead reactor on GaN growth,” Materials, vol. 12, p. 3375, 2019, doi:10.3390/ma12203375. Available: https://www.mdpi.com/1996-1944/12/20/3375/html
X-Ray Diffractometer (XRD and HRXRD) page of this vault.
Photoluminescence Spectrometer page of this vault.
Quantum Well LED (InGaN-GaN and AlGaInP) page of this vault.

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MOCVD Reactor