Claim Missing Document
Check
Articles

Found 12 Documents
Search

N-Type Conductivity in Wurtzite Mn-Doped GaN thin Films Grown by Plasma Assisted MOCVD Budi Mulyanti; Agus Subagio; Edi Supriyanto; Heri Sutanto; Fitri Suryani Arsyad; Pepen Arifin; Maman Budiman; Mohamad Barmawi
Jurnal Matematika & Sains Vol 11, No 2 (2006)
Publisher : Institut Teknologi Bandung

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

Abstract

Ferromagnetic semiconductor GaN:Mn thin films were successfully grown by plasma-assisted metalorganic chemical vapor deposition (PA-MOCVD) method on c-plane sapphire substrate. The films were grown at various Mn source flux in the range of 5 - 40 sccm and growth temperature which was lower than that of MOCVD themal, i.e. in the range of 625-700 °C. Cyclopentadienyl manganese tricarbonyl (CpMnT) was used as a source of Mn. X-ray diffraction patterns confirmed that GaN:Mn films are wurtzite and do not show second phase for film with Mn concentration up to 6.4% at 650 °C of growth temperature. Hall effect measurements show n-type characteristics. The carrier (electron) density tends to decreases and Hall mobility tends to with the increase of Mn concentration is increased. Hysteresis curves observed from VSM measurements indicated that all of the samples are ferromagnetic at room temperature.
Pengaruh Bentuk dan Fluktuasi Ukuran Dot terhadap Pelebaran Garis Spektral Inhomogen pada Quantum Dot Gallium Nitrida (QD GaN) Fitri Suryani Arsyad; Budi Mulyanti; Amiruddin Supu; Moehamad Barmawi
Jurnal Matematika & Sains Vol 12, No 4 (2007)
Publisher : Institut Teknologi Bandung

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

Abstract

Theoretical analysis of the phenomena of the size fluctuation in Gallium Nitride quantum dot (GaN QD) is presented inthis paper. The effect of QD size fluctuation on the electron and hole energy level and the inhomogeneous linebroadening is studied. Analytical expressions for the inhomogeneous line broadening are derived for a Gaussian sizefluctuation distribution. Decreasing in the QD carrier energy level is observed when QD size increases. The peak ofoptical transition energy probability (Emax) is shifted to higher energy when dot size fluctuation (σL) increases. Theoptical transition energy distribution (fE) of cylindrical QD is at the higher energy with the inhomogeneous linebroadening (σE) wider than those of conical, ellipsoidal, as well as semi ellipsoidal QD.
Karakteristik Life Time dan Efisiensi Modul Surya Berbasis Pewarna Menggunakan Interkoneksi Seri Febriana, Iqbal; Muliani, Lia; Mulyanti, Budi
Jurnal Elektronika dan Telekomunikasi Vol 15, No 1 (2015)
Publisher : Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1443.731 KB) | DOI: 10.14203/jet.v15.28-32

Abstract

Sel surya berbasis pewarna atau yang dikenal dengan dye-sensitized solar cell (DSSC) merupakan sel surya generasi baru yang bekerja berdasarkan photoelectrochemical. Proses absorpsi cahaya dilakukan oleh molekul pewarna (dye) dan proses pemisahan muatan oleh bahan semikonduktor anorganik (dalam penelitian ini digunakan TiO2). Dalam penelitian ini dilakukan pabrikasi modul surya menggunakan lapisan partikel nano TiO2 (non-scattering) dan menggunakan campuran lapisan partikel nano TiO2 dengan lapisan partikel sub-mikron TiO2 (scattering). Tujuan penelitian ini adalah untuk mengetahui waktu hidup (life time) dan efisiensi modul surya dengan bahan yang berbeda. Pabrikasi modul surya ini menggunakan teknik screen printing. Karakteristik life time diperoleh dari hasil pengukuran I-V yang dilakukan secara manual menggunakan lampu LED 15 Watt dengan intensitas 40 mW/cm2 . Pengujian life time dilakukan selama 500 jam, dan hasilnya menunjukkan bahwa modul surya dengan lapisan scattering dapat mempengaruhi karakteristik life time namun efisiensi yang didapatkan kurang baik yaitu sebesar 0,31% sedangkan modul surya dengan lapisan non-scattering menunjukkan efisiensi yang baik yaitu sebesar 1,83% namun karakteristik life time yang kurang baik.
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.
Simple, Easy-use and Low-cost Software for Design of Single and Cascaded Microring Resonators Using Semi-numerical Method Budi Mulyanti; Lilik Hasanah; Tommi Hariyadi; Arjuni B Pantjawati; Heru Yuwono; P. Susthita Menon; Sahbudin Shaari
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 13, No 3: September 2015
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v13i3.1733

Abstract

Development of a simple, easy and low-cost software for designing of waveguide-coupled single and cascaded microring resonator (MRRs) using semi-numerical calculation based on transfer matrix method (TMM), is presented in this paper. The software uses a device model which is embedded on the high index contrast (HIC) structure of silicon-on-insulator (SOI) with monomodal cavity for TE-mode polarizations, operating around 1550 nm optical wavelength. The main aim of the software is to estimate the microring resonator performance parameters, such as free spectral range (FSR) and quality factor (Q-factor). The software is very simple and easy to use. With a standard laptop computer, it only takes few seconds to obtain transmission response, FSR and Q-factor of single MRR for varied waveguides separation distance and ring radius. The results were then verified using simulation method based on finite integration technique using 3D electromagnetic simulator, which need a high memory and processor of computer and take days to execute the simulation. We found only small discrepancy, which in averages are about 4.25% and 10.80% for FSR and Q-factor, respectively. In general, the results obtained from this software are closer to 3D electromagnetic simulation results.
Low-Cost Fiber Optic Chemical Sensor Development for Fishpond Application Budi Mulyanti; Yuski Maolid Rizki Faozan; Ajuni B. Pantjawati; Roer Eka Pawinanto; Lilik Hasanah; Wahyu Sasongko Putro
TELKOMNIKA (Telecommunication Computing Electronics and Control) Vol 16, No 6: December 2018
Publisher : Universitas Ahmad Dahlan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/telkomnika.v16i6.10493

Abstract

In this study, aimed to develop low-cost sensor based on fiber optic to assess ammonia index for fishpond application. Here, the simple design was proposed by using Evanescent wave type to assess ammonia index during acid rain event. The experiment result showed maximum absorption loss with variation ammonia mass 1~5% with wavelength 1310 nm from Optical Light Source (OLS) is 27.56 dBm while Optical Spectrum Analyzer (OSA) reached 25.86 dBm. We had calculated RMSE, MAE, and Percent Error (PE) value both of the device (Low-cost fiber optic chemical sensor and OSA) are 1.692%, 0.916%, and 98.833% respectively. A good result from low cost fiber optic chemical sensor has successful developed with lowest production less than 1,455 USD per-year.
Distance Learning in Vocational High Schools during the COVID-19 Pandemic in West Java Province, Indonesia Mulyanti, Budi; Purnama, Wawan; Pawinanto, Roer Eka
Indonesian Journal of Science and Technology Vol 5, No 2 (2020): IJOST: VOLUME 5, ISSUE 2, 2020
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v5i2.24640

Abstract

This study aims to investigate (1) the availability of learning facilities for distance learning (or online learning), (2) the ability of students and teachers to utilize the learning facilities, and (3) how distance learning activities take place at public or private vocational high schools, specifically whether it is perceived to be more interesting than ordinary learning. This study used a survey method to obtain data and a quantitative descriptive method to analyze the data. The type of data in this study was primary based on the responses of respondents or individuals from groups representing the population of public and private vocational high schools, especially in the Electrical Engineering Clusters in the entire areas of West Java. The results revealed that online learning has been carried out in many public and private vocational high schools in West Java. This study indicates that the availability of online learning facilities, the utilization of facilities, and the online learning process in public vocational high schools were better than those in private vocational high schools. In general, students of both public and private vocational high schools stated that online learning is not more interesting than ordinary learning, although most of them can understand the lessons taught and they were given an opportunity by their teachers to actively participate during the learning process.
A Design and performance analysis of a telemetry system for remote monitoring of turbidity of water during the COVID-19 pandemic Hasanah, Lilik; Hakim, Wahyu Luqmanul; Aminudin, Ahmad; Sahari, Siti Kudnie; Mulyanti, Budi
Indonesian Journal of Science and Technology Vol 5, No 2 (2020): IJOST: VOLUME 5, ISSUE 2, 2020
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/ijost.v5i2.24705

Abstract

A turbidity telemetry system for COVID-19 pandemic situations using nRF24L01+transceiver and SEN0189 water turbidity sensor-based microcontroller has been successfuly  developed.. The method used to characterize the sensor is by comparing sensor output voltages with the value of water turbidity. Turbid water used was created by adding distilled water with a concentration of sediment obtained from the filtered sediment with less than 60 μm in diameter. Data transmission performance for various transmit power was done by calculating the error percentages by comparing the number of messages sent by transmitter and received by receiver. The transmit power settings were 0, -6, -12, and 18 dBm and variations in the distance of data transmission from 10 to 80 m. The test results show that the water turbidity sensor has a good measurement range in measuring turbidity of water from 1.873 to 3500 NTU. Higher concentrations of sediment and turbidity of the water made the sensor output voltage decrease. There was a decrease in output voltage in the value, namely -0.0006 in turbidity sensor sensitivity. The results also show an increase in error percentages as the distance of data transmission increases, while the bigger the transmit power is used for data transmission, the smaller the percentage of errors occurs.
ANTENA MIKROSTRIP MONOPOLE PITA LEBAR SEGI EMPAT UNTUK APLIKASI DVB-T Ratna Nurvitasari; Tommi Haryadi; Budi Mulyanti
ELECTRANS Vol 13, No 2 (2014): Volume 13, Nomor 2, Tahun 2014
Publisher : Universitas Pendidikan Indonesia

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

Abstract

Pada makalah ini dilakukan perancangan dan fabrikasi antena mikrostrip monopole berbentuk segi empat untuk aplikasi Digital Video Broadcasting-Terestrial (DVB-T) pada frekuensi 478-694 MHz. Sebelum fabrikasi, terlebih dahulu dilakukan simulasi menggunakan perangkat lunak 3D Electromagnetic Simulator. Berdasarkan hasil simulasi, nilai return loss kurang dari -10 dB diperoleh  pada rentang  frekuensi 478-882 MHz, gain antena sebesar 1-3 dBi, dan pola radiasi omnidirectional. Fabrikasi Antena mikrostrip menggunakan substrat FR-4 dengan konstanta dielektrik 4,65 dan tebal 1,6 mm. Hasil pengukuran menunjukkan bahwa antena ini dapat diaplikasikan untuk DVB-T di Indonesia.
Karakteristik Life Time dan Efisiensi Modul Surya Berbasis Pewarna Menggunakan Interkoneksi Seri Iqbal Febriana; Lia Muliani; Budi Mulyanti
Jurnal Elektronika dan Telekomunikasi Vol 15, No 1 (2015)
Publisher : LIPI Press

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.14203/jet.v15.28-32

Abstract

Sel surya berbasis pewarna atau yang dikenal dengan dye-sensitized solar cell (DSSC) merupakan sel surya generasi baru yang bekerja berdasarkan photoelectrochemical. Proses absorpsi cahaya dilakukan oleh molekul pewarna (dye) dan proses pemisahan muatan oleh bahan semikonduktor anorganik (dalam penelitian ini digunakan TiO2). Dalam penelitian ini dilakukan pabrikasi modul surya menggunakan lapisan partikel nano TiO2 (non-scattering) dan menggunakan campuran lapisan partikel nano TiO2 dengan lapisan partikel sub-mikron TiO2 (scattering). Tujuan penelitian ini adalah untuk mengetahui waktu hidup (life time) dan efisiensi modul surya dengan bahan yang berbeda. Pabrikasi modul surya ini menggunakan teknik screen printing. Karakteristik life time diperoleh dari hasil pengukuran I-V yang dilakukan secara manual menggunakan lampu LED 15 Watt dengan intensitas 40 mW/cm2 . Pengujian life time dilakukan selama 500 jam, dan hasilnya menunjukkan bahwa modul surya dengan lapisan scattering dapat mempengaruhi karakteristik life time namun efisiensi yang didapatkan kurang baik yaitu sebesar 0,31% sedangkan modul surya dengan lapisan non-scattering menunjukkan efisiensi yang baik yaitu sebesar 1,83% namun karakteristik life time yang kurang baik.