Advanced LIGO Photodiode Development ______

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Advanced LIGO Photodiode Development______

• David B. Jackrel, Homan B. Yuen, Seth R. Bank,
  Mark A. Wistey, Xiaojun Yu, Junxian Fu, Zhilong
  Rao, and James S. Harris, Jr.
• Solid State Research Lab, Stanford University
• LSC Meeting LLO
• March 22nd, 2005

LIGO-G050116-00-Z
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Outline

• AdLIGO Photodiode Specifications
• Device Results
• Damage Threshold
• AdLIGO Devices
• Future Directions

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Advanced LIGO Schematic
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Photodiode Specifications
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Rear-Illuminated PD Advantages

• High Power
• Linear Response
• High Speed

Conventional PD
Adv. LIGO Rear-Illuminated PD
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Materials Analysis InGaAs/GaAs vs. GaInNAs/GaAs

• X-Ray Diffraction
• Transmission Electron Microscopy
• Surface Roughness Mapping
• Photoluminescence
• Deep-Level Transient Spectroscopy
• Absorption Spectra
• Etc.

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Device Internal Quantum Efficiency (Low Power
50 mW)
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External Quantum Efficiency Thick Substrate
Ext. Efficiency
Bias (Volts)
Optical Power (mW)
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Damage Threshold LLO Devices (9/23/03)
P gt 2e6 W/cm2 (???) (gt180 W in 100 ?m spot)
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LHO Damaged PDs Shutter Problems (2/22/05)
Damaged Devices
Undamaged Devices
acoustic coupling -Robert Schofield
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LHO Damaged PDs Shutter Problems (2/18/05)
No injected Peak at 280 Hz
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Rear-IlluminatedDamage-Threshold Test
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Front-IlluminatedDamage-Threshold Test
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AdLIGO Devices
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AdLIGO Devices Commercial Vendors
http//www.stanford.edu/djackrel
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In Progress / Future Directions

• Substrate removal
• GaInNAs(Sb) growth (w/ upgraded system)
• ARC
• 1/f noise experiments
• Successor - Zhilong Rao
• Packaging devices / Testing components
• Higher saturation power? (? RF detection?)
• Surface uniformity?, Backscatter?, etc.

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Future Directions What types of diodes are
needed?

• Quantum Efficiency?
• Damage Threshold?
• Saturation Power?
• RF detection
• AdLIGO laser stabilization
• Electronic Noise?
• DC
• RF? (180 MHz)
• Frequency Response?
• Commercially available?
• Other???

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XRD Reciprocal Space Map (004)
MM-InGaAs
GaInNAs
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Surface Roughness
MM-InGaAs RMS 6.2 nm
110
-110
GaInNAs RMS 0.8 nm
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Optimizing Post-Growth Anneal
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Scanning PhotoluminescenceIntensity
InGaAs Uniformity 10.8
GaInNAs Uniformity 15.9
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Scanning PL Intensity Maps
InGaAs
GaInNAs
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GaInNAs Temp. Dependent PL Localization Energy
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Deep Level Transient SpectroscopyMajority
Carrier Traps
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1 ?m GaInNAs Film Transmission
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2 ?m InGaAs Absorption Spectrum
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InGaAs vs. GaInNAs Dark I Density
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Dark and Photocurrent (SNR)
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Photovoltaic Response
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C-V Curves
GaInNAs 1/RC ? 7 MHz
InGaAs 1/RC ? 15 MHz
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LCR Resonant Circuit Modeling
FWHM ? 15 MHz
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Damage Threshold Tests