Analisis Mikrostruktur thin film ZnO pada Si dan thin film ZnO pada Cu

Telah dilakukan analisa mikrostruktur dari thin film ZnO pada substrat Si dan Cu. thin film dibentuk dengan menggunakan teknik berbasis laser yang dikenal dengan Pulsed Laser Deposition (PLD). Laser yang digunakan dalam pembentukan thin film adalah laser Nd-YAG pulsa dengan panjang gelombang 532 nm, energi 75 mJ dan frekuensi 10 Hz. Substrat (Si dan Cu) dan sampel (pelet ZnO) diletakkan pada ruang vakum pada tekanan 5 Torr, dengan iradiasi laser selama 5 menit (3000 shoots). thin film yang dihasilkan berbentuk lapisan-lapisan seperti pelangi dengan bagian tengah berwarna putih. thin film kemudian dikarakterisasi dengan menggunakan SEMEDX pada tiga titik yang berbeda yaitu titik tengah, titik kiri dan titik kanan. Hasil SEM menunjukkan bahwa thin film mempunyai lapisan ZnO tidak merata. Hasil lapisan menunjukkan lapisan paling banyak dibagian tengah yang berwarna putih dibandingkan di bagian kiri dan kanan . Dimana prosentase massa Si dibagian tengah 0%, Zn (31,33%) dan massa O (20,56%). Sedangkan prosentase massa Si dibagian kiri (82,1%) lebih besar dibandingkan massa Zn (3,81%) dan massa O (8,6%). Dan pada titik kanan komposisi Si juga lebih besar dengan massa (83,26%) dibandingkan Zn (3,55%) dan massa O (8,38%). Hal yang sama juga ditunjukkan padalapisan ZnO pada substrat Cu. Dimana prosentase massa Cu dibagian tengah lebih kecil (5,39%) dibandingkan prosentase massa Zn (40,66%) dan massa O (16,66%). Sedangkan pada titik kiri prosentase massa Cu lebih besar (91,43%) dibandingkan massa Zn (1,8%) dan massa O (3,81%). Dan pada titik kanan massa Cu memilki prosentase lebih besar (81,59%) dibandingkan massa Zn (2,61%) dan massa O (4,82%)

Quantitative Analysis of Liquid by Quick Freezing Into Ice Using Nd-YAG Laser-Induced Atmospheric Plasma

A new approach of quantitative analysis of liquid sample using laser ablation technique was developed. The liquid was immediately freezed using the mixture of dry ice and alcohol in weight ratio of 95% : 5%. As a result, an increase of the repulsion force from the sample surface will enable the generation of the laser-induced shock wave plasma which was difficult to carry out on liquid surface. The ice sample was then irradiated using Nd-YAG laser operated in its fundamental wavelength. In order to increase the signal to background ratio and to obtain a sharp atomic line spectra, helium gas was used instead of air. Dynamic characterization of the spatially integrated time profile of the Cu I 521.8 nm, Cu I 510.5 nm and Hα lines shows a shock excitation stage and cooling stage which is corresponded to our shock wave model even when the plasma was generated under atmospheric gas pressure. Further study of the time profile averaged temperature of the atmospheric plasma also shows an increase of temperature during the shock excitation stage followed by diminution of temperature during the cooling stage. An application of this technique was then applied to quantitative analysis of several liquid samples. A linear calibration curve which intercept at 0 point was obtained for all of the elements investigated in this study such as sodium, potassium, lithium, copper, silver, lead and aluminum. A detection limit of around 1 ppm was found for the above element. This new technique will contribute to a great extent of laser atomic emission spectrochemical analysis for liquid samples