Stavarache Ionel, Teodorescu Valentin Serban, Prepelita Petronela, Logofatu Constantin, Ciurea Magdalena Lidia
National Institute of Materials Physics, 405A Atomistilor Street, 077125, Magurele, Ilfov, Romania.
National Institute for Laser, Plasma and Radiation Physics, 409 Atomistilor Street, 077125, Magurele, Ilfov, Romania.
Sci Rep. 2019 Jul 16;9(1):10286. doi: 10.1038/s41598-019-46711-w.
In this work we prepared films of amorphous germanium nanoparticles embedded in SiO deposited by magnetron sputtering on Si and quartz heated substrates at 300, 400 and 500 °C. Structure, morphology, optical, electrical and photoconduction properties of all films were investigated. The Ge concentration in the depth of the films is strongly dependent on the deposition temperature. In the films deposited at 300 °C, the Ge content is constant in the depth, while films deposited at 500 °C show a significant decrease of Ge content from interface of the film with substrate towards the film free surface. From the absorption curves we obtained the Ge band gap of 1.39 eV for 300 °C deposited films and 1.44 eV for the films deposited at 500 °C. The photocurrents are higher with more than one order of magnitude than the dark ones. The photocurrent spectra present different cutoff wavelengths depending on the deposition temperature, i.e. 1325 nm for 300 °C and 1267 nm for 500 °C. These films present good responsivities of 2.42 AW (52 μW incident power) at 300 °C and 0.69 AW (57 mW) at 500 °C and high internal quantum efficiency of ∼445% for 300 °C and ∼118% for 500 °C.
在本工作中，我们通过磁控溅射在300、400和500°C加热的硅和石英衬底上制备了嵌入SiO中的非晶锗纳米颗粒薄膜。研究了所有薄膜的结构、形态、光学、电学和光电导性能。薄膜深度处的锗浓度强烈依赖于沉积温度。在300°C沉积的薄膜中，锗含量在深度上是恒定的，而在500°C沉积的薄膜中，从薄膜与衬底的界面到薄膜自由表面，锗含量显著降低。从吸收曲线中，我们得到300°C沉积薄膜的锗带隙为1.39 eV，500°C沉积薄膜的锗带隙为1.44 eV。光电流比暗电流高一个多数量级。光电流光谱呈现出取决于沉积温度的不同截止波长，即300°C时为1325 nm，500°C时为1267 nm。这些薄膜在300°C时具有2.42 AW（入射功率52 μW）的良好响应度，在500°C时具有0.69 AW（57 mW）的良好响应度，300°C时的内量子效率约为445%，500°C时约为118%。
