Tuesday, December 25, 2018

Enhanced mobility in organic field-effect transistors due to semiconductor/dielectric interface control and very thin single crystal


A perfect organic crystal while keeping high quality semiconductor/dielectric interface with minimal defects and disorder is crucial for the realization of high performance organic single crystal field-effect transistors (OSCFETs). However, in most reported OSCFET devices, the crystal transfer processes is extensively used. Therefore, the semiconductor/dielectric interface is inevitably damaged. Carrier traps and scattering centers are brought into the conduction channel, so that the intrinsic high mobility of OSCFET devices is entirely disguised. Here, very thin pentacene single crystal is grown directly on bare SiO2 by developing a 'seed-controlled' pentacene single crystal method. The interface quality is controlled by an in situ fabrication of OSCFETs. The interface is kept intact without any transfer process. Furthermore, we quantitatively analyze the influence of crystal thickness on device performance. With a pristine interface and very thin crystal, we have achieved the highest mobility: 5.7 cm2 V−1 s−1—more than twice the highest ever reported pentacene OSCFET mobility on bare SiO2. This study may provide a universal route for the use of small organic molecules to achieve high performance in lamellar single crystal field-effect devices.


Source:IOPscience

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Wednesday, December 12, 2018

Preparation and characterization of high-quality perovskite CH3NH3PbX3 (I, Br) single crystal


In this paper, inverse temperature crystallization and top-seed solution growth method are used to grow high-quality perovskite CH3NH3PbX3 (I, Br) single crystal. The maximum crystal diameter is 6 mm for CH3NH3PbI3, and 3 mm for CH3NH3PbBr3. The results of XRD show that the crystals are tetragonal structure for CH3NH3PbI3, cubic crystal orientation for CH3NH3PbBr3. What is more, crystals exhibit excellent stability in air and can be maintained for eight months. Furthermore, the crystal growth processes are described in detail. The results demonstrate that CH3NH3PbBr3 single crystal growth is more sensitive to the environment.



Source:IOPscience

For more information, please visit our website: www.semiconductorwafers.net,