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

最近，在GaN基材料中成功地实现了蓝光LED和LD。第三族氮化物是当今最有希望用于新型光电子设备的系统。然而，在材料科学和第三族氮化物的晶体生长方面仍有许多需要澄清的问题。事实上，就在最近，有几位研究人员报告说，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。最近观察到生长在熔融石英玻璃上的多晶GaN层具有很强的光致发光。GaN的这种光致发光特性与传统的III-V半导体如GaAs有很大的不同。预计在Inn等其他氮化物半导体中也会观察到同样的不同寻常的性质。本工作研究了射频反应溅射沉积的GaN和InN的薄膜性质。主要研究结果如下：1.非晶态GaN：H薄膜在室温下观察到了较强的发光。峰值能量为3.27 eV.2。目前，发光的起源和发光机制尚不清楚。我们认为光致发光峰来源于几乎无定形薄膜中的小尺寸晶态GaN。3.InN的带隙能量与溅射条件有关。溅射InN薄膜禁带附近的光学性质有待进一步研究。4.In和Si复合靶反应溅射制备的InN：Si薄膜的结晶、电学和光学性能随Si含量的不同而变化很大。

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.