Transient Grating Spectrometer
Carrier diffusion coefficientin a matter of minutes
Non-invasive
measurement techniqueFully automated andcomputer controlled
Continuous setting ofgrating period
Sensitivity down to µJ/cm²
excitation level
Advanced measurement
and analysis software
Photoluminescence (PL)measurement option

Specifications
Model

HARPIA-TG is a transient grating spectrometer for the measurementof carrier diffusion and lifetime. Measurements are based on thelaser-induced transient grating (LITG) technique. This method enables
simultaneous observation of non-equilibrium carrier recombinationand diffusion by all‑optical means.

HARPIA-TG

Grating recording wavelength

340 – 560 nm

1)

Probe wavelength 2)

1030 nm

Grating period

1.15 – 15 μm3)

Pulse duration< 290 fs

Delay range

Up to 8 ns

HARPIA-TG allows the characterization of electrically non‑conductive
or non-fluorescent samples. It is suitable for semiconductors materials
and derivatives, e.g., silicon carbide (SiC), gallium nitride (GaN),
perovskites, organic and inorganic solar cells, quantum dots, and evencomplex nanostructures such as quantum wells.

MEASUREMENT RANGES
Diffusion coefficient0.1 – 50 cm2/s

Carrier lifetime

1 ps – 80 ns1)

Extendable to long-wave VIS/NIR. Contact
sales@lightcon.com for details.

DIMENSIONS
Physical dimensions (L × W × H)

730 × 420 × 188 mm2)

SH (515 nm) or OPA-based probe is available uponrequest. Contact sales@lightcon.com for details.

3)

Depends on the excitation wavelength.

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

CLASS 4 LASER PRODUCTHARPIA-TG principal scheme

ODLProbe beam∆τdttemins
Tra oberp

PD
Pump beamPD

Beam separator

teacffr e
Di robp

CH BSdSample

PDBSCHODLPDPMθΔτ

– beam splitter– chopper– optical delay line
– photodiode– parabolic mirror– intersection angle– delay

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Performance
GaN

Diffusion length of GaN
as a function of fluence

0.8

1.5

1.0

0.4

0.6
Front-side
Back-side

0.4
0.2
0.0

10100
Excitation fluence, µJ/cm²

Diffusion length, µm

Front-side
Back-side

Carrier lifetime, ns

Diffusion coefficient, cm²/s2.50.51030 nm probe wavelength.

Carrier lifetime of GaN
as a function of fluence

Diffusion coefficient of GaN
as a function of fluence

2.0structural quality and higher defect density at the interface between
the sapphire substrate and GaN. Measurements were performed
using HARPIA-TG combined with CARBIDE-CB5 laser and I-OPA.
Measurement conditions: 60 kHz, 355 nm pump wavelength,

100.3
Front-side
Back-side

0.2
0.1
0.0

100
Excitation fluence, µJ/cm²

10100
Excitation fluence, µJ/cm²SiC
Silicon carbide (SiC) is a compound semiconductor with uniqueproperties, valued for its high thermal conductivity, wide bandgap,
and excellent electrical performance. In SiC devices, wherehigh-frequency, high-temperature, and high-voltage operationis common, managing carrier diffusion is particularly critical toensure efficient and reliable device performance, making it a key
consideration in SiC semiconductor technology.

Carrier lifetime of SiC
as a function of fluence

Diffusion coefficient of SiC
as a function of fluence

Diffusion length of SiC
as a function of fluence
0.8

1.50

2.75
2.50
2.25
2.00Diffusion length, µm

1.25

3.00

Carrier lifetime, ns

Diffusion coefficient, cm2/s

3.25

1.00
0.75
0.50
0.25

1020501000.00

10Excitation fluence, µJ/cm²

2050
Excitation fluence, µJ/cm²

100

0.7
0.6
0.5
0.4
0.3

102050
Excitation fluence, µJ/cm²Drawings

Recommended layout

HARPIA-TG drawing

HARPIA-TG with CARBIDE-CB5 and I-OPA

125

747
730

1000 mm

30Inputs(optional)

440
420

Inputs

36 55

184.5
188.3

30833
831
747

125

Inputs(optional)

1000 mm

www.phototechnica.co.jp
REV. 240522 | SALES@LIGHTCON.COM100〒336-0017 埼玉県さいたま市南区南浦和 1-2-17

TEL:048-871-0067 FAX:048-871-0068

e-mail:voc@phototechnica.co.jp

Femtosecond Lasers | Wavelength-Tunable Sources | OPCPA Systems | Spectroscopy Systems | Microscopy Sources | Applications

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