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12 results on '"Gulo, Desman Perdamaian"'

3. Tungsten Nitride (W5N6): An Ultraresilient 2D Semimetal

Author

Chin, Hao-Ting, primary, Wang, Deng-Chi, additional, Gulo, Desman Perdamaian, additional, Yao, Yu-Chi, additional, Yeh, Hao-Chen, additional, Muthu, Jeyavelan, additional, Chen, Ding-Rui, additional, Kao, Tzu-Chun, additional, Kalbáč, Martin, additional, Lin, Ping-Hui, additional, Cheng, Cheng-Maw, additional, Hofmann, Mario, additional, Liang, Chi-Te, additional, Liu, Hsiang-Lin, additional, Chuang, Feng-Chuan, additional, and Hsieh, Ya-Ping, additional

Published
2023
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8. Tungsten Nitride (W5N6): An Ultraresilient 2D Semimetal

Author

Chin, Hao-Ting, Wang, Deng-Chi, Gulo, Desman Perdamaian, Yao, Yu-Chi, Yeh, Hao-Chen, Muthu, Jeyavelan, Chen, Ding-Rui, Kao, Tzu-Chun, Kalbáč, Martin, Lin, Ping-Hui, Cheng, Cheng-Maw, Hofmann, Mario, Liang, Chi-Te, Liu, Hsiang-Lin, Chuang, Feng-Chuan, and Hsieh, Ya-Ping

Abstract

Two-dimensional transition metal nitrides offer intriguing possibilities for achieving novel electronic and mechanical functionality owing to their distinctive and tunable bonding characteristics compared to other 2D materials. We demonstrate here the enabling effects of strong bonding on the morphology and functionality of 2D tungsten nitrides. The employed bottom-up synthesis experienced a unique substrate stabilization effect beyond van-der-Waals epitaxy that favored W5N6over lower metal nitrides. Comprehensive structural and electronic characterization reveals that monolayer W5N6can be synthesized at large scale and shows semimetallic behavior with an intriguing indirect band structure. Moreover, the material exhibits exceptional resilience against mechanical damage and chemical reactions. Leveraging these electronic properties and robustness, we demonstrate the application of W5N6as atomic-scale dry etch stops that allow the integration of high-performance 2D materials contacts. These findings highlight the potential of 2D transition metal nitrides for realizing advanced electronic devices and functional interfaces.

Published
2024
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9. Beam Shaping Assembly (BSA) Design Based D-D Neutron Generator 2,45 MeV For BNCT Treatment Facility

Author

Gulo, Desman Perdamaian, Trihandaru, Suryasatriya, and Santoso, Slamet

Subjects
neutron yield, BSA, BNCT, neutron epitermal, MNCPX
Abstract

Salah satu terapi kanker yang sedang dikembangkan saat ini adalah metode Boron Neutron Capture Therapy (BNCT).Dalam mendukung uji fasilitas BNCT pada kanker yang berada di bawah permukaan kulit seperti kanker payudara dibutuhkan suatu generator yang dapat menghasilkan neutron epitermal. Salah satu generator yang dapat menghasilkan neutron adalah D-D neutron generator dengan energi sebesar 2,45 MeV. Dari hasil perhitungan pada makalah ini, didapatkan produksi neutron per detik (neutron yield) dari Neutron Generator (NG) milik PSTA-BATAN Yogyakarta sebesar 2,55×1011 n/s. Energi dan fluks tersebut termasuk dalam range neutron cepat. Oleh sebab itu perlu dimoderasi ke level neutron epitermal yakni pada interval energi antara 1eV sampai 10KeV dengan fluks sebesar 109 n/cm2s. Nilai ini merupakan rekomendasi standar IAEA. Untuk memoderasi neutron cepat tersebut dibutuhkan suatu desain Beam Shaping Assembly (BSA) yang berfungsi untuk memoderasi neutron cepat ke level neutron epitermal. Salah satu bagian BSA yang berperan dalam memoderasi neutron cepat ke neutron epitermal adalah moderator.Pada makalah ini bahan moderator yang digunakan adalah MgF2 dan AlF3.Moderator tersebut diatur ketebalannya hingga memenuhi standar IAEA menggunakan perangkat lunak MCNPX. Dari hasil simulasi optimasi moderator BSA, didapatkan fluks epitermal sebesar 4,64×108 n/cm2/s untuk kedua bahan moderator dengan ketebalan moderator masing-masing 15 cm. Dari hasil penelitian ini, nilai fluks epitermal tersebut masih belum tercapai sesuai dengan standar IAEA. Hal ini disebabkan karena fluks neutron yang dihasilkan dari NG masih relatif kecil sehingga masih belum bisa digunakan untuk uji fasilitas BNCT pada kanker yang berada di bawah kulit seperti kanker payudara. Boron Neutron Capture Therapy (BNCT) is one of the cancer treatments that are being developed in nowadays. In order to support BNCT treatment for cancer that exists in underneath skin like breast cancer, the facility needs a generator that is able to produce epithermal neutron. One of the generator that is able to produce neutron is D-D neutron generator with 2,45 MeV energy. Based on the calculation of this paper, we found that the total production of neutron per second (neutron yield) from Neutron Generator (NG) by PSTA-BATAN Yogyakarta is 2,55×1011 n/s. The energy and flux that we found is in the range of fast neutron. Thus, it needs to be moderated to the level of epithermal neutron which is located in the interval energy of 1 eV to 10 KeV with 109 n/cm2s flux. This number is the recommendation standard from IAEA. Beam Shaping Assembly (BSA) is needed in order to moderate the quick neutron to the level of epithermal neutron. One part of BSA that has the responsibility in moderating the quick neutron to epithermal neutron is the moderator. The substance of moderator used in this paper is MgF2 and A1F3. The thickness of moderator has been set in in such a way by using MCNPX software in order to fulfill the standard of IAEA. As the result of optimizing BSA moderator, the data obtain epithermal flux with the total number of 4,64×108 n/cm2/s for both of moderators with the thickness of moderator up to 15 cm. At the end of this research, the number of epithermal flux does not follow the standard of IAEA. This is because the flux neutron that is being produced by NG is relatively small. In conclusion, the NG from PSTA-BATAN Yogyakarta is not ready to be used for the BNCT treatment facility for the underneath skin cancer like breast cancer.

Published
2015

10. Nontrivial Raman Characteristics in 2D Non-Van der Waals Mo5N6

Author

Yao, Ching-Hsiang, Gao, Hongze, Ping, Lu, Gulo, Desman Perdamaian, Liu, Hsiang-Lin, Tuan Hung, Nguyen, Saito, Riichiro, and Ling, Xi

Abstract

Resonant Raman spectra of a two-dimensional (2D) non-van der Waals (vdW) material, molybdenum nitride (Mo5N6), are measured across varying thicknesses, ranging from a few to tens of nanometers. Fifteen distinct Raman peaks are observed experimentally, and their assignments are made using first-principles calculations for the most stable AABB-stacking structure of Mo5N6. The assignments are further supported by angular-dependent Raman measurements for all peaks, except the most intense one at 215 cm–1. Calculations reveal that the 215 cm–1peak does not appear for three-dimensional molybdenum nitrides and is not a first-order Raman-active mode. We further investigated the origin of the 215 cm–1peak and assigned it as a defect-induced double-resonance peak. Moreover, thickness-dependent Raman measurements reveal that both the 215 and 540 cm–1peaks─assigned to out-of-plane and in-plane modes, respectively─blue shift as thickness increases, reaching a plateau around 20 nm. This thickness-dependent Raman shift over a wide thickness range is nontrivial compared to other common vdW 2D materials and is attributed to the much stronger stacking interaction between the constituent layers in non-vdW materials. This finding highlights Raman spectroscopy as a valuable tool for characterizing the thickness of 2D non-vdW materials.

Published
2024
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11. Characterizing temperature-dependent optical properties of (MA0.13FA0.87) PbI3 single crystals using spectroscopic ellipsometry.

Author

Chen, Hsiao-Wen, Gulo, Desman Perdamaian, Chao, Yu-Chiang, and Liu, Hsiang-Lin

Subjects
ELLIPSOMETRY, PHOTONS, SINGLE crystals, ABSORPTION spectra, BAND gaps
Abstract

In this paper, we present spectroscopic ellipsometry measurements of (MA0.13FA0.87)PbI3 single crystals assessed at photon energies of 0.73–6.42 eV and at temperatures between 4.4 and 400 K. At room temperature, the refractive index was dispersed as a function of frequency, which is typical of a semiconductor. The absorption spectrum exhibited several electronic transitions. We estimated a room temperature direct band gap of 1.66 ± 0.02 eV and exciton binding energy of 40 meV. With decreasing temperature, the refractive index increased. The room-temperature thermo-optic coefficients were −1.7 × 10−4 and −2.5 × 10−4 K−1 at wavelength of 600 and 1200 nm. The exciton peak position and bandgap energy exhibited a redshift, which was attributed to a reverse ordering of the band structures. Additionally, an anomaly in exciton peak position and bandgap occurred at approximately 100–200 K due to the structural phase transition. This phenomenon was associated with the coexistence of MA/FA-disordered and MA/FA-ordered domains. Our results provide a foundation for the technological development of lead halide perovskites-based photonic devices at various temperatures. [ABSTRACT FROM AUTHOR]

Published
2019
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12. Tungsten Nitride (W 5 N 6 ): An Ultraresilient 2D Semimetal.

Author

Chin HT, Wang DC, Gulo DP, Yao YC, Yeh HC, Muthu J, Chen DR, Kao TC, Kalbáč M, Lin PH, Cheng CM, Hofmann M, Liang CT, Liu HL, Chuang FC, and Hsieh YP

Abstract

Two-dimensional transition metal nitrides offer intriguing possibilities for achieving novel electronic and mechanical functionality owing to their distinctive and tunable bonding characteristics compared to other 2D materials. We demonstrate here the enabling effects of strong bonding on the morphology and functionality of 2D tungsten nitrides. The employed bottom-up synthesis experienced a unique substrate stabilization effect beyond van-der-Waals epitaxy that favored W 5 N 6 over lower metal nitrides. Comprehensive structural and electronic characterization reveals that monolayer W 5 N 6 can be synthesized at large scale and shows semimetallic behavior with an intriguing indirect band structure. Moreover, the material exhibits exceptional resilience against mechanical damage and chemical reactions. Leveraging these electronic properties and robustness, we demonstrate the application of W 5 N 6 as atomic-scale dry etch stops that allow the integration of high-performance 2D materials contacts. These findings highlight the potential of 2D transition metal nitrides for realizing advanced electronic devices and functional interfaces.

Published
2024
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