Low Dimensional Semiconductors – LDS
Responsible: Reinhard Schwarz
Deposition and opto-electronic characterization of semiconducting, insulating, and ferroelectric thin films.
Hybrid PLD/CVD reactor:
Technological basis for thin film deposition is a UHV reactor chamber together with a pulsed Nd:YAG laser system for hybrid PLD/CVD processes. Therefore, solid (e.g. Si, Zn, Cu) and gaseous sources (O, N) can be used. The laser can be operated at 3 wavelengths, 1064 nm, 532 nm, and 266 nm, with a maximum 300 mJ pulse energy and 5 ns pulse duration. The CVD process is powered by a 100 W RF-generator at 13.56 MHz. PC-control of process parameters allows for simultaneous or sequential process protocols. The reactor system is designed for fast gas switching for attaining sharp interfaces. Separate vacuum chambers are available for either semiconductor-oxide material system deposition or ferroelectric film preparation.
Low temperature equipment:
An optical OXFORD bath cryostat is used for transport and for photoluminescence measurements in the temperature range between 80 K and 500 K. Both steady-state excitation by HeNe (633 nm), HeCd lasers (325 nm), and Xe light sources, together with various spectrometers, and pulsed laser excitation by Nd:YAG laser are possible.
Contact-less measurement of carrier mobility and recombination lifetime is accessible with a microwave resonator system operated at 2.45 GHz.
Location: IST-Alameda, Pav. Física, floors 3 and 5
For all equipment, short-term access at any time for interested colleagues is welcome. Please, contact the scientific researchers in charge.
Semiconductor Materials and Energy Conversion – SMECL
Responsible and contacts: Ana Maria Amaral, ext: 3208
The laboratory is equipped with a range of systems for thin film deposition, materials processing and characterization. The current areas of research include: amorphous silicon materials and devices, transparent and conductive oxides and their applications and crystalline silicon solar cells and electronic devices.
Materials deposition systems:
– Plasma Enhanced Chemical Vapor Deposition (PECVD), equipped with gases SiH4, PH3/SiH4(2,5%), B2H6/H2(2%), NH3, CH4, H2, Ar
– Plasma Enhanced Reactive Thermal Evaporation (PERTE)
– Diffusion furnace (up to 1000 °C) – Thermolab, custom-made
– Physical Vapor Deposition (PVD) by thermal evaporation
Materials processing systems:
– Reactive Ion Etcher (RIE) using SF6 and/or O2
– Photolithography and other chemical processing:
- Spinner Laurell WS-650MZ-23NPP
- UV exposure system (without micro-alignment);
- Thermal plate (up to 300 °C);
- Muffle (up to 300 °C);
- Ultra-pure water dispenser (Milli-Q – Direct-8)
- Ultra-sonic bath.
- Metalographic microscope (1000x max. magn.)
– Electrical characterization systems:
- Conductivity vs temperature (-20 to 80 ºC), in vacuum
- I(V) curves under dark conditions or under illumination (AM1.5), room temperature, up to 4 terminal devices
- I(V) curves under dark conditions or under illumination (AM1.5), vs temperature, up to 2 terminal devices
- C(V) measurements at room temperature
– Profilometer – Veeco Dektak3 (res. 20 nm)
– Infra-red spectrophotometer (FTIR) – Shimadzu IRAffinity-1, wavenumber range: 7800 – 350 cm-1 (res. 0.5 cm-1)
– Four-point probe – Veeco FPP 5000
– UV-Vis-IR spectrophotometer – Shimadzu UV3100, 180 – 3100 nm (res. 1 nm).
Access conditions: Within collaborative research work. Contact the scientific researcher in charge.
Location: IST-Alameda, Complexo Interdisciplinar, 6th floor.