LAB 06. Photo-/Electrical and Magnetic Characterizations

Recirculated Liquid He Cryostat 1

Janis Research, USA

Specifications:

• Closed-loop liquid Helium (He)
• Temperature range: 3 – 300 K
• Equipped with an electromagnet:
• Variable magnetic field: up to 1 T
• Computer-assisted system for data acquisition, control and automation using LabVIEW (National Instruments)

Applications:

• Temperature-dependent electric and magnetic studies
• Four-point measurements ("Van der Pauw" configuration)
• Electric transport and magnetotransport in nanostructures
• Magnetoresistance and Hall effect

Recirculated Liquid He Cryostat 2

Janis Research, USA

Specifications:

• Closed-loop liquid Helium (He)
• Temperature range: 3 – 300 K
• Equipped with a LASER (Spectra-Physics, USA)
• Computer-assisted system for data acquisition, control and automation using LabVIEW (National Instruments)

Applications:

• Temperature-dependent electrical measurements
• Four-point measurements ("Van der Pauw" configuration)
• Current-voltage characteristics under monochromatic light
• Electric transport in nanostructures

Solar Simulator

Newport-Oriel 150, USA

Specifications:

• 150 W Xenon arc lamp
• Adjustable light intensity up to "1 Sun"
• AM 1.5 standard, 100 mW/cm²
• Monochromator Newport 74100, USA
• Computer-assisted system for data acquisition, control and automation using LabVIEW (National Instruments)

Applications:

• Current-voltage characteristics under illumination
• Determination of conversion efficiency
• Advanced characterization of photovoltaic cells:
• Open-circuit voltage and short-circuit current
• Series and shunt resistances of solar cells
• Fill factor

Accessories, consumables and auxiliary tools available in the lab:

• Two optical powermeters Newport 1936-R and 2931-C, USA, used for optical power measurements and for the determination of the External Quantum Efficiency (EQE) of solar cells, photodetectors, and other optoelectronic devices.
• A Keithley 6517A electrometer (Tektronix, USA), designed for the measurement of ultra-low currents, voltages, electric charge and extremely high resistances. The instrument is used for the characterization of insulating materials, electronic and optoelectronic devices, as well as for the determination of electrical resistivity and charge transport properties.
• Two Keithley SourceMeter units, models 2450 and 2400 (Tektronix, USA).
• A Keithley 2010 digital multimeter (Tektronix, USA).
• A dual-channel digital lock-in amplifier SRS SR830 (Stanford Research Systems, USA), designed for the detection and measurement of extremely low-amplitude electrical signals in the presence of background noise through synchronous detection ("lock-in") techniques.
• Sample holders and positioning stages with fine multi-axis adjustment capabilities.
• Optical filters, apertures, lenses and optomechanical mounts for photoelectrical measurements.
• Electrical contacts, clamps, connectors, spring-loaded pins and auxiliary accessories for establishing reliable experimental electrical connections.
• Sets of reference resistors, passive electronic components and test boards.
• Low-temperature measurement accessories, including cryogenic cables, sample holders, and cryostat-compatible components.
• Consumable materials for establishing electrical contacts, including silver paste, conductive tapes and bonding wires.
• Tweezers available in a variety of shapes, sizes, and functional configurations, manufactured from stainless steel, Teflon and other laboratory-compatible materials, used for the manipulation and transfer of sensitive samples and specimens.
• Computers dedicated to data acquisition and processing, equipped with specialized software for instrument control, automation and data analysis.
• Laboratory gloves, lab coats, safety goggles and other personal protective equipment.