Claim Missing Document
Check
Articles

Found 2 Documents
Search
Journal : Journal of Mathematical and Fundamental Sciences

Effect of Growth Temperature and Mn Incorporation on GaN:Mn Thin Films Grown by Plasma-Assisted MOCVD Budi Mulyanti; A. Subagio; F. S. Arsyad; P. Arifin; M. Barmawi; Irzaman Irzaman; Z. Jamal; U. Hashim
Journal of Mathematical and Fundamental Sciences Vol. 40 No. 2 (2008)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/itbj.sci.2008.40.2.1

Abstract

In this paper, the growth of GaN:Mn thin films by plasma-assisted metalorganic chemical vapor deposition (PAMOCVD) method is reported. The method used in this study, utilizes a microwave cavity as a cracking cell to produce nitrogen radicals, which in turn reduce the growth temperature. Trimethylgallium (TMGa), nitrogen (N2) and cyclopentadienyl manganese tricarbonyl (CpMnT) were used as a source of Ga, N and Mn, respectively, while hydrogen gas was used as a carrier gas for both TMGa and CpMnT. The effect of growth temperature and Mn incorporation on structural properties and surface morphology of GaN:Mn films are presented. The growth of GaN:Mn thin films were conducted at varied growth temperature in range of 625 oC to 700 oC and the Mn/Ga molar fraction in the range of 0.2 to 0.5. Energy dispersive of X-ray (EDX) and X-ray diffraction (XRD) methods were used to analyze atomic composition and crystal structure of the grown films, respectively. The surface morphology was then characterized using both atomic force microscopy (AFM) and scanning electron microscopy (SEM) images. A systematic XRD analysis reveal that maximum Mn incorporation that still produces single phase GaN:Mn (0002) is 6.4 % and 3.2 % for the film grown at 650 oC and 700 oC, respectively. The lattice constant and full width at half maximum (FWHM) of the single phase films depend on the Mn concentration. The decrease in lattice constant accompanied by the increase in FWHM is due to incorporation of substitutional Mn on the Ga sub-lattice. The maximum values of doped Mn atoms incorporated in the wurtzite structure of GaN:Mn as substitutional atoms on Ga sub-lattice are 2.0 % and 2.5 % at 650 oC and 700 oC, respectively. AFM and SEM images show that the film grown at lower growth temperature and Mn concentration has a better surface than that of film grown at higher growth temperature and Mn concentration.
Simulation and Fabrication of Double Barrier Structure of P-I-N Amorphous Silicon (a-Si) Device Ida Hamidah; Kardiawarman Kardiawarman; Budi Mulyanti; Andi Suhandi
Journal of Mathematical and Fundamental Sciences Vol. 33 No. 1 (2001)
Publisher : Institute for Research and Community Services (LPPM) ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Abstract. The application of double barrier (DB) structure in p-i-n amorphous silicon (a-Si) device was studied. The theoretical study was done to obtain device parameters such as tunneling probability and current density. The tunneling probability was calculated by employing the Schroedinger equation, WKB approximation and Green function. Width of potential well, width and height of barrier were varied to obtain the highest tunneling probability value. The current density was contributed by diffusion, and tunneling current densities. It was found that current density had a peak of 3950 A/m2 at 0.56 volt forward bias. Furthermore, the fabrication of p-i-n a-Si device with double barrier structure was successfully carried out. To realize the double barrier structure, optimization of optical band gap of barrier a-SiC:H was done by varying ratio of CH4 to [CH4+SiH4]. The fabrication of p-i-n a-Si device was then done by using Plasma Enhanced Chemical Vapor Deposition (PECVD) technique with a structure of glass substrate/TCO/p-a-Si:H (2.15 eV;140Ã…)/i-a-Si:H (1.81 eV;1800 Ã…)/barrier a-SiC:H (2.36 eV;45 Ã…)/potential well i-a-Si:H (1/81 eV; 30 Ã…)/barrier a-SiC:H (2.36 eV; 45 Ã…)/n-a-Si:H (1.81 eV;180 Ã…)/Al. The I-V characteristic of the device showed a peak current calue at 0.55 forward bias. Simulasi dan Fabrikasi Struktur Double Barrier pada Divais Amorphous SiliconSari. Aplikasi struktur double barrier (DB) pada divais amorphous silicon (a-Si) telah dilakukan untuk memperoleh beberapa parameter divais seperti probabilitas tunneling dan rapat arus. Probabilitas tunneling dihitung dengan menerapkan persamaan Schroedinger, pendekatan WKB dan fungsi Green. Lebar sumur potensial, lebar dan tinggi barrier telah divariasikan untuk memperoleh harga probabilitas tunneling yang maksimum. Rapat arus total dari divais dalam perhitungan ini merupakan jumlah dari rapat arus difusi dan rapat arus tunneling. Diperoleh bahwa rapat arus total memiliki nilai maksimum sebesar 3950 A/m2 pada tegangan bias maju 0,56 volt. Selanjutnya, telah berhasil juga difabrikasi divais p-i-n a-Si dengan struktur double barrier. Didapatkan bahwa karakteristik I-V dari divais menunjukkan adanya puncak rapat arus pada tegangan bias maju 0,55 volt.ihamidah@eudoramail.com