PENGARUH TEMPERATUR SUBSTRAT TERHADAP KUALITAS KRISTAL LAPISAN TIPIS Sn(S0,2Te0,8) HASIL PREPARASI TEKNIK EVAPORASI VAKUM THE EFFECT OF SUBSTRATE TEMPERATURE VARIATIONS ON THE CRYSTAL QUALITY AND CHEMICAL COMPOSITION OF THE Sn(S0,2Te0,8) THIN FILMS PREPARATION BY VACUUM EVAPORATION METHOD

Abstract

Abstrak

Penelitian ini bertujuan untuk menumbuhkan lapisan tipis Sn(S_0,2Te_0,8) dengan teknik evaporasi vakum untuk mempelajari karakter lapisan tipis Sn(S_0,2Te_0,8) sebagai semikonduktor dengan karakterisasi struktur kristal, morfologi permukaan, dan komposisi kimia. Preparasi dilakukan pada tekanan (5 x 10^-5) mbar dengan melakukan variasi temperatur substrat. Temperatur substrat divariasi sebanyak 4 kali, yaitu 250ºC, 300ºC, 350ºC, dan 400ºC. Sampel dikarakterisasi menggunakan XRD (X-Ray Diffraction) untuk mengetahui struktur kristal, SEM (Scanning Electron Microscopy) untuk mengetahui morfologi permukaan, dan EDS (Energy Dispersive Spectroscopy) untuk mengetahui komposisi kimia. Hasil menunjukkan bahwa keempat sampel memiliki struktur kristal kubik dengan parameter kisi menggunakan metode analitik, sampel 1 (temperatur substrat 250ºC): a = b = c = 6,049 Å, sampel 2 (temperatur substrat 300°C): a = b = c = 6,109 Å, sampel 3 (temperatur substrat 350ºC): a = b = c = 6,259 Å, sampel 4 (temperatur substrat 400ºC): a = b = c = 6,442 Å, sedangkan parameter kisi dengan metode Le Bail, sampel 1 (temperatur substrat 250ºC): a = b = c = 6,281 Å, sampel 2 (temperatur substrat 300ºC): a = b = c = 6,317 Å, sampel 3 (temperatur substrat 350ºC):   a = b = c = 6,327 Å, sampel 4 (temperatur substrat 400ºC): a = b = c = 6,327 Å. Variasi temperatur substrat menyebabkan perbedaan kualitas kristal lapisan tipis tiap sampel, yang ditandai dengan adanya perbedaan intensitas spektrum. Permukaan lapisan tipis homogen terdiri atas butiran berukuran (~0,2) µm dan ketebalan lapisan tipis (~0,6) µm. Lapisan tipis mengandung unsur Sn, S, dan Te dengan persentase komposisi kimia Sn = 52,31%, S = 0,88%, dan Te = 46,81%. Perbandingan molaritas Sn : S : Te adalah 1,04 : 0,02 : 0,94.

Kata kunci: semikonduktor, lapisan tipis Sn(S_0,2Te_0,8), teknik evaporasi

Abstract

This research aims to grow Sn(S_0,2Te_0,8) thin films by vacuum evaporation method to study characterization of Sn(S_0,2Te_0,8) thin films as smiconducter materials which includes characterization of the crystal structure, surface morphology, and chemical composition. The preparation prosess were performed on (5 x 10^-5) mbar pressure with substrate temperature variations. The substrate temperatures were varied for four times, namely 250ºC, 300ºC, 350ºC and 400ºC. Samples were characterized by XRD (X-Ray Diffraction) to determine the crystal structure, SEM (Scanning Electron Microscopy) to determine the surface morphology, and EDS (Energy Dispersive Spectroscopy) to determine the chemical composition. The result showed that the four samples had cubic crystal structure with the lattice parameters using analitical method were sample 1 (the substrate temperature was 250ºC): a = b = c = 6.049 Å, sample 2 (the substrate temperature was 300ºC): a = b = c = 6.109 Å, sample 3 (the substrate temperature was 350ºC):  a = b = c = 6.259 Å, and sample 4 (the substrate temperature was 400ºC): a = b = c = 6.442 Å, while the lattice parameters using Le Bail method were sample 1: a = b = c = 6.281 Å, sample 2: a = b = c = 6.317 Å, sample 3: a = b = c = 6.327 Å, sample 4: a = b = c = 6.327 Å. The substrate temperature variations caused the difference in thin films quality, marked by the difference of spectrum intensity. The surface of sample was homogenous and consisted of grains with (~0,2) µm size and (~0,6) µm thickness. Thin film contains elements of Sn, S, and Te with the chemical composition percentages were Sn = 52.31%, S = 0.88%, and    Te = 46.81%. So, the molarity comparisons of Sn : S : Te was 1,04 : 0.02 : 0.94.

Keywords: semiconductor, Sn(S_0,2Te_0,8) thin films, vacuum evaporation method