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Technical Info

In a conventional solar cell, the value of the forbidden band determines both current and voltage. High values produce low currents (just a few photons are absorbed) and high voltages, and vice versa. There is an optimum which is theoretically oriented towards the silicon forbidden band (for isotropic solar illumination) . A. Luque y A. Martí (UPM) proposed in 1997 the convenience of placing an intermediate band (IB) allowed in the middle of the semiconductor forbidden band. According to a procedure patented by this team, the solar cell is formed up by placing the intermediate band material between two ordinary semiconductors: one of them n-type for contacting the conduction band (CB) and the other, p-type, for contacting the valence band (VB). The intermediate band is therefore isolated from the metallic contacts.

A set of advanced characterization tools has been grouped in a Laboratory called IBLAB (Intermediate Band LABoratory) and includes, for example, quantum efficiency measurements capable of detecting the two-photon below bandgap absorption, photoluminescence, electroluminescence, photoreflectance, current-voltage characteristics under concentrated light and cryogenic temperatures, AFM, FTIR, DLTS, etc

MAIN FEATURES :

Determination of semiconductor gap by photoreflectance*
Characterization of the quantum efficiency of novel solar cells*
Capability to obtain the current-voltage characteristics of solarcells in dark and in illumination conditions, up to concentrations of 2500x and at low temperatures*
Study of the behavior of novel semiconductors and devices under concentration up to 10.000x. This test can be performed at low temperatures (*)
Performance of FTIR tests in order to determine the optical absorption coefficient of photovoltaic materials mainly in the infrared*
Undertaking of DLTS measurements to study semiconductor defects*
Measurement of photoluminescence and electroluminescence of materials and solar cells*
Capability to determine roughness of the semiconductor surface*
3D Fabrication

(*) Under ISO9001 STANDARD

EQUIPMENT

Photoreflectance

Specifications according to ISO9001 (I-18-05)
Type of materials: Semiconductors
Metallization: NO
Thickness: <10mm
Size <0.5cmx0.5cm
Range of measurement: 400nm-2500nm

2. Quantum efficiency

Specifications according to ISO9001 (I-18-05)
Type of materials : 2 terminal Semiconductor Devices
Metallization: YES (grid)
Thickness: <5mm
Size <4cmx4cm
Range of measurement: 400nm-1700nm
Low Temperature Measurement Optional (see below)

3. Current-Voltage Characteristics

Specifications according to ISO9001 I-18-05
Type of materials : 2 terminal Semiconductor Devices
Metallization: YES
Thickness: <5mm
Size <1cmx1cm
Range of measurement: 100nA-1A
Low Temperature Measurement Optional (see below)

4. Concentration Measurements

Specifications according to ISO9001 I-18-05
Type of materials : 2 terminal Semiconductor Devices
Metallization: YES
Thickness: <5mm
Size <1cmx1cm
Range of measurement: 1uA-6A & 10ºC-50ºC
Low Temperature Measurement Optional (see below)

5. FTIR

Specifications according to ISO9001 I-18-05
Type of materials: semiconductors
Metallization: NO
Thickness: <5mm
Size >1cmx1cm
Range of measurement: 800nm-20000nm

6. Deep level Transient Spectroscopy (DLTS)

Specifications according to ISO9001 I-18-05
Type of materials: 2 terminal Semiconductor Devices
Metallization: YES
Thickness: <5mm
Size
Range of measurement: 77K-330K

7. Photoluminiscence

Specifications according to ISO9001 I-18-05
Type of materials: semiconductors
Metallization: NO
Thickness: <5mm
Size >0.5cmx0.5cm
Range of measurement: 300nm-2000nm

8. Electroluminiscence

Specifications according to ISO9001 I-18-05
Type of materials: 2 terminal semiconductor Devices
Metallization: YES
Thickness: <5mm
Size < 0.5cmx0.5cm
Range of measurement: 300nm-2000nm

9. Profiler

Specifications according to ISO9001 I-18-05
Type of materials: non viscous materials
Metallization:--
Thickness: <30mm
Size

LIMITATIONS OR CONSTRAINTS :

The UPM IB SC group offer opportunities to access to their facility by filling-in the specific form. Information about applied RATES can be found here

TYPICAL SERVICES OR RESULTS

Characterization of semiconductors and devices for both research centers and companies
Assessment on the characterization results
Evaluation of intermediate band effects in different semiconductors: two-photon below bandgap absorption and voltage preservation under concentrated light.
3D printing service