Growth and interface properties of Au Schottky contact on ZnO grown by molecular beam epitaxy

6th Vacuum and Surface Sciences Conference of Asia and Australia

Asghar, M.^1 ; Mahmood, K.^1 ; Malik, Faisal^1 ; Hasan, M.A.^2

Department of Physics, Islamia University of Bahawalpur, 63100, Pakistan^1

Department of Electrical and Computer Engineering, UNC, Charlotte, NC 28223, United States^2

关键词: Contact properties;    Density of interface state;    E beam evaporation;    Frequency-dependent capacitance;    Interface property;    Inverse proportions;    Measuring frequency;    Series resistances;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/439/1/012031/pdf
DOI  :  10.1088/1742-6596/439/1/012031

来源: IOP

【 摘 要 】

In this paper, we have discussed the growth of ZnO by molecular beam epitaxy (MBE) and interface properties of Au Schottky contacts on grown sample. After the verification of structure and surface properties by X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM), respectively, Au metal contact was fabricated by e-beam evaporation to study contact properties. The high value of ideality factor (2.15) and barrier height (0.61 eV) at room temperature obtained by current-voltage (I-V) characteristics suggested the presence of interface states between metal and semiconductor. To confirm this observation we carried out frequency dependent capacitance-voltage (C-V) and conductance-voltage (G-V) demonstrated that the capacitance of diode decreased with increasing frequency. The reason of this behavior is related with density of interface states, series resistance and image force lowering. The C-2-V plot drawn to calculate the carrier concentration and barrier height with values 1.4×1016cm-3and 0.92 eV respectively. Again, high value of barrier height obtained from C-V as compared to the value obtained from I-V measurements revealed the presence of interface states. The density of these interface states (Dit) was calculated by well known Hill-Coleman method. The calculated value of Ditat 1 MHz frequency was 2×1012eV-1cm-2. The plot between interface states and frequency was also drawn which demonstrated that density of interface states had inverse proportion with measuring frequency.