The current–voltage and capacitance–voltage characterization of the Au/Methylene Blue/n-GaAs organic-modified Schottky diodes

Authors : Abdullah AKKAYA

Pages : 756-767

View : 13 | Download : 7

Publication Date : 2018-09-01

Article Type : Research Paper

Abstract :We report the electrical properties of the Au/n–GaAs devices with and without thin organic interface layer. Methylene blue insert ignore into journalissuearticles values(MB); is a heterocyclic aromatic chemical compound with the molecular formula C16H18N3SCl. The MB layer was formed by spin coating technique on chemically cleaned gallium arsenide insert ignore into journalissuearticles values(GaAs); substrate. The current–voltage insert ignore into journalissuearticles values(I–V); and the frequency dependent capacitance–voltage insert ignore into journalissuearticles values(C–V); characteristics of the Au/MB/n–GaAs metal-insulator-semiconductor insert ignore into journalissuearticles values(MIS); and Au/n–GaAs metal-semiconductor insert ignore into journalissuearticles values(MS); devices have been investigated at room temperature. The MS and MIS devices I–V characteristics the showed a good rectification, and they were analyzed based on the thermionic emission insert ignore into journalissuearticles values(TE); theory. The ideality factor insert ignore into journalissuearticles values(n); and the barrier height insert ignore into journalissuearticles values(Φbinsert ignore into journalissuearticles values(IV);); from the I–V characteristics was determined as 1.131±0.006 and 0.782±0.005 eV for MS device and 1.336±0.057 and 0.950±0.008 eV for MIS device, respectively. A Cheung’s method and modified Norde`s function has been used to extract the parameters including the insert ignore into journalissuearticles values(Φb); and the series resistance insert ignore into journalissuearticles values(RS);. Also the values of the barrier height obtained from the C–V measurements insert ignore into journalissuearticles values(Φbinsert ignore into journalissuearticles values(CV);); of the MS and MIS was 0.863±0.034 eV and 1.187±0.093 eV, at 1 MHz, respectively.Distributions of the interface state density insert ignore into journalissuearticles values(Dit); of the MS and MIS devices were derivate from I–V and C–V measurements. Our results indicates that the Au/MB/n–GaAs device had lower interface state density values than the Au/GaAs device. Also non-saturated reverse bias current investigated by the using a Pole-Frenkel emission model. Furthermore, the optical and morphological properties of MB layer were investigated by the Atomic Force Microscopy insert ignore into journalissuearticles values(AFM);, Scanning Electron Microscopy insert ignore into journalissuearticles values(SEM); and UV-vis Spectrophotometer insert ignore into journalissuearticles values(UV-vis);.Finally, we showed that, increasing Φb and decreasing Dit and improving electrical parameters of MIS devices indicates that, thin MB interface layer could prefer for modification of Au/n–GaAs devices.
Keywords : Metal interfacial layer semiconductor structures, Methylene Blue, Schottky barrier, Series resistance, Interface states