Properties of group-III nitride semiconductor thin films deposited by RF sputtering.

近年来，在GaN基材料中成功地实现了蓝光LED和LD。III族氮化物是当今最有前途的新型光电子器件系统。然而，在III族氮化物的材料科学和晶体生长方面仍有许多问题需要澄清。事实上，最近，一些研究人员报告说，InN的带隙不是通常的1.9 eV，而是可能小于1 eV。因此，通常的1.9 eV的带隙能量是值得怀疑的。最近，在熔融石英玻璃上生长的多晶GaN层观察到强的光致发光发射（PL）。GaN的这种PL性质与传统的III-V族半导体如GaAs完全不同。预计在InN等其他氮化物半导体中也会观察到同样不寻常的性质。本文研究了射频反应溅射沉积GaN和InN薄膜的特性。结果表明：1.室温下，非晶GaN：H薄膜具有较强的光致发光。峰值能量为3.27eV。2.发光的起源和发光机制尚不清楚。我们认为发光峰起源于非晶薄膜中的小尺寸晶体GaN。3. InN的带隙能量依赖于溅射条件。溅射沉积的InN：Si薄膜在带隙附近的光学性质有待进一步研究。4. In和Si复合靶反应溅射沉积的InN：Si薄膜的晶体、电学和光学性质随Si含量的变化而变化。

Recently, blue LED and LD were successfully achieved in the GaN based materials. The group III nitrides are today the most promising system for new photo-electronics devices. However, many points which must be clarified were remained in the material sciences and crystal growth of the group III nitrides. In fact, very recently, several researchers have reported that the bandgap of InN is not usual 1.9 eV, but may be less than 1 eV. Therefore, the usual band gap energy of 1.9 eV is doubtful. Strong photoluminescence emission (PL) was recently observed for the polycrystalline GaN layer grown on fused silica glass. Such PL property of GaN is quite different from conventional III-V semiconductors like GaAs. The same unusual properties were expected to observe in the other nitride semiconductors like InN. This work was studied about the film properties of the deposited GaN and InN by rf reactive sputtering. The results are follows.1.Strong PL was observed for the amorphous GaN : H films in room temperature. The peak energy value is 3.27 eV.2.The origin and luminescence mechanism of PL are not clear yet. We considered that the PL peak originate from small size crystalline GaN in the almost amorphous film.3.The bandgap energy of InN depends on sputtering conditions. The optical properties near the bandgap energy of sputter deposited InN films should be still further studying.4.The crystalline, electric and optical properties of InN : Si films deposited by reactive sputtering from In and Si composite targets vary largely with dependence on Si contents.