Effect of thermal annealing on the electrical characteristics of an amorphous ITZO:Li thin film transistor fabricated using the magnetron sputtering method

Organic phototransistors capable of absorbing in the visible light spectrum without color filters are the best alternatives to conventional inorganic phototransistors. In this study, the effect of illumination on the electrical characteristics of a solution-processed poly(3-hexylthiophene): 6,13-bis(triisopropylsilylethynyl) pentacene-blend thin-film transistor (TFT) was investigated. The wavelengths of the irradiated light were determined from the absorbance spectrum of the blended film and changes in the transistor’s electrical characteristics were explained in relation to the electrical and light absorption properties of each component material. The photosensitivity and absorbing properties of the blended TFT were enhanced at 515 and 450 nm and exhibited positively shifted threshold voltages under incident light. The results indicated that the photo-generated exci-ton pair characteristics matched the absorbance properties of the blended material and that the absorption and photocurrent characteristics of the respective components could be combined. This process for the heterogeneous blending of organic semiconductors has the potential to improve phototransistor performance and contribute to the development of broadband absorbing phototransistors.

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Electrical and Structural Characteristics of Excimer Laser-Crystallized Polycrystalline Si1−xGex Thin-Film Transistors

Materials ◽

10.3390/ma12111739 ◽

2019 ◽

Vol 12 (11) ◽

pp. 1739 ◽

Cited By ~ 2

Author(s):

Kyungsoo Jang ◽

Youngkuk Kim ◽

Joonghyun Park ◽

Junsin Yi

Keyword(s):

Thin Film ◽

Grain Size ◽

Energy Density ◽

Excimer Laser ◽

Density Of States ◽

Silicon Germanium ◽

Structural Characteristics ◽

Thin Film Transistor ◽

Electrical Characteristics ◽

Starting Point

We investigated the characteristics of excimer laser-annealed polycrystalline silicon–germanium (poly-Si1−xGex) thin film and thin-film transistor (TFT). The Ge concentration was increased from 0% to 12.3% using a SiH4 and GeH4 gas mixture, and a Si1−xGex thin film was crystallized using different excimer laser densities. We found that the optimum energy density to obtain maximum grain size depends on the Ge content in the poly-Si1−xGex thin film; we also confirmed that the grain size of the poly-Si1−xGex thin film is more sensitive to energy density than the poly-Si thin film. The maximum grain size of the poly-Si1−xGex film was 387.3 nm for a Ge content of 5.1% at the energy density of 420 mJ/cm2. Poly-Si1−xGex TFT with different Ge concentrations was fabricated, and their structural characteristics were analyzed using Raman spectroscopy and atomic force microscopy. The results showed that, as the Ge concentration increased, the electrical characteristics, such as on current and sub-threshold swing, were deteriorated. The electrical characteristics were simulated by varying the density of states in the poly-Si1−xGex. From this density of states (DOS), the defect state distribution connected with Ge concentration could be identified and used as the basic starting point for further analyses of the poly-Si1−xGex TFTs.

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