Characterization
Organic semiconductors differ from inorganic counterparts in many ways. These include optical, electronic, chemical and structural properties. In order to design and model the organic semiconductors, such optical properties as absorption and photoluminescence need to be characterized. Optical characterization for this class of materials can be done using UV-visible absorption spectrophotometers and photoluminescence spectrometers. Semiconductor film appearance and morphology can be studied with atomic force microscopy (AFM) and scanning electron microscopy (SEM). Electronic properties such as ionisation potential can be characterized by probing the electronic band structure with ultraviolet photoelectron spectroscopy (UPS).
The charge-carrier transport properties of organic semiconductors are examined by a number of techniques. For example, time-of-flight (TOF) and space charge limited current techniques are used to characterize “bulk” conduction properties of organic films. Organic field effect transistor (OFET) characterization technique is probing “interfacial” properties of semiconductor films and allows to study the charge carrier mobility, transistor threshold voltage and other FET parameters. OFETs development can directly lead to novel device applications such as organic-based flexible circuits, printable radio frequency identification tags (RFID) and active matrix backplanes for displays. Chemical composition and structure of organic semiconductors can be characterized by infrared spectroscopy, secondary ion mass spectrometry (SIMS) and X-ray photoelectron spectroscopy (XPS).
Read more about this topic: Organic Semiconductors