| Summary: | 碩士 === 國立臺灣科技大學 === 材料科學與工程系 === 105 === In this research, we successfully deposited donor-acceptor co-substituted ZnSnGaN films by radio-frequency reactive sputtering technique with single cermet targets in an Ar/N2 atmosphere. ZnxSn0.04GaN (x= 0, 0.03, 0.06 and 0.09) films were deposited on Si (100) substrates at 400 oC with RF output power at 120 watt. X-ray diffraction results showed that ZnSnGaN films had a wurtzite structure with a preferential (10-10) growth plane. The film transformed into p-type conduction at x= 0.06. The highest conductivity was found to be 0.16 S·cm^-1 for the Zn0.09Sn0.04GaN film due to the high hole concentration of 3.3x10^17 cm^-3. The values of band gap for ZnxSn0.04GaN films were found in the range of 2.89 – 3.12 eV.
The comparison among Zn0.06Sn0.04GaN films deposited at various RF powers of 90, 120 and 150 W indicated that crystalline quality was improved with RF power. As power increased to 150 watt, the carrier concentration increased to 5.1x10^17 cm^-3 and conductivity was 1.1 S·cm^-1. The energy bandgap of Zn0.06Sn0.04GaN films decreased from 3.22 to 2.92 eV, as power increased from 90 to 150 watt.
When substrate temperature was increased from 100 oC to 400 oC, the crystallinity increased with temperature. The 400 oC-deposited film had the highest hole concentration and electrical conductivity. It is found that the optical band gap of the Zn0.06Sn0.04GaN films slightly decreased with increasing temperature.
In addition, the p-n junction ZnxSn0.04GaN diodes were all fabricated successfully by sputtering technique with cermet targets for p- and n-type ZnxSn0.04GaN and metal targets for electrodes. The current-voltage curves of the p-n diode tested at room temperature were performed. The I-V curves exhibited rectifying behavior. By using equations based on the standard thermionic-emission (TE) mode, the barrier height and ideality factor of the diodes were also determined.
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