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Transient Grating Spectrometer
FEATURES

ᰋ Carrier diffusion coefficient in a matter of minutes!
ᰋ Non-invasive measurement techniqueᰋ Fully automated and computer controlledᰋ Continuous setting of grating period

ᰋ Sensitivity down to µJ/cm² excitation levelᰋ Advanced measurement and analysis software
ᰋ Photoluminescence (PL) measurement option

HARPIA-TG is a transient grating spectrometer for themeasurement of carrier diffusion and lifetime. Measurements
are based on the laser-induced transient grating (LITG)
technique. This method enables simultaneous observationof non-equilibrium carrier recombination and diffusion by
all‑optical means.
HARPIA-TG allows the characterization of electrically
non‑conductive or non-fluorescent samples. It is suitable forsemiconductors materials and derivatives, e.g., silicon carbide(SiC), gallium nitride (GaN), perovskites, organic and inorganic
solar cells, quantum dots, and even complex nanostructures
such as quantum wells.

SPECIFICATIONSModel

HARPIA-TG

Grating recording wavelength 1)

340 – 560 nm

Probe wavelength 2)
Grating period

1030 nm1.15 – 15 μm

3)Pulse duration< 290 fs

Delay range

Up to 8 ns

MEASUREMENT RANGES
Diffusion coefficient

0.1 – 50 cm2/s

Carrier lifetime

1 ps – 80 ns

Extendable to long-wave VIS/NIR.
Contact sales@lightcon.com for details.
2)
SH (515 nm) or OPA-based probe isavailable upon request. Contact
sales@lightcon.com for details.
3)
Depends on the excitation wavelength.
1)

DANGER: VISIBLE AND/OR INVISIBLE
LASER RADIATION AVOID EYE OR SKINEXPOSURE TO DIRECT, REFLECTEDOR SCATTERED RADIATION

CLASS 4 LASER PRODUCTODL

Probe beamΔτedittsm benao
Tr prPDPDPump beamdteac effr ob
Di prBeam separator
CH BSSamplePD

Principal scheme of HARPIA-TG

66

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GaN
The graphs below indicate the carrier diffusion coefficient,diffusion length, and lifetime of GaN at the back and at the frontof the layer as a function of fluence. The thicker the GaN, thebetter the quality of the grown layer due to better coalescence.
It is evidenced by the lower diffusivity and shorter lifetimes

2.0
1.5

1.0
0.5

0.8

0.4

0.6

0.3

Front-side
Back-side

0.4
0.2
0.0

10100
Excitation fluence, µJ/cm2Diffusion coefficient of GaN as a function of fluence

Diffusion length, µm

Front-side
Back-side

Carrier lifetime, ns

Diffusion coefficient, cm2/s

2.5that indicate poor structural quality and higher defect density
at the interface between the sapphire substrate and GaN.
Measurements were performed using HARPIA-TG combined withCARBIDE-CB5 laser and I-OPA. Measurement conditions: 60 kHz,355 nm pump wavelength, 1030 nm probe wavelength.

10Front-side
Back-side

0.2
0.1
0.0

100
Excitation fluence, µJ/cm2Carrier lifetime of GaN as a function of fluence

10100
Excitation fluence, µJ/cm2Diffusion length of GaN as a function of fluence

SiC

3.00
2.75
2.50
2.25
2.00

and high-voltage operation is common, managing carrier
diffusion is particularly critical to ensure efficient and reliable
device performance, making it a key consideration in SiC
semiconductor technology.

1.50

0.8

1.250.7Diffusion length, µm

3.25

Carrier lifetime, nsDiffusion coefficient, cm2/s

Silicon carbide (SiC) is a compound semiconductor withunique properties, valued for its high thermal conductivity,wide bandgap, and excellent electrical performance.
In SiC devices, where high-frequency, high-temperature,

1.00
0.75
0.50
0.25

102050
Excitation fluence, µJ/cm2100

Diffusion coefficient of SiC as a function of fluence

0.00

102050
Excitation fluence, µJ/cm2Carrier lifetime of SiC as a function of fluence

DRAWINGS

102050
Excitation fluence, µJ/cm2100Diffusion length of SiC as a function of fluence

36 55

747

Inputs(optional)

7477301000 mm300.3440420

Inputs

0.4125833831125(optional)

300.5

RECOMMENDED LAYOUT

184.5
188.3

Inputs1000.6SCIENTIFIC APPLICATIONS | MICROSCOPY SOURCES | SPECTROSCOPY SYSTEMS | OPCPA SYSTEMS | WAVELENGTH-TUNABLE SOURCES | FEMTOSECOND LASERSPERFORMANCE

1000 mm

Drawing of HARPIA-TG

Recommended layout with CARBIDE-CB5 and I-OPA

www.phototechnica.co.jp
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e-mail:voc@phototechnica.co.jp