Apart from collaborating with RIKEN Nishina Center since 2007, Federal Institute for Materials Research and Testing (BAM) Berlin, Germany, since 2013 and Synchrotron Light Research Institute (SLRI), Thailand, since 2016 he has also been networking with a number of universities in Japan, Taiwan, Southeast Asian countries and Europe. These collaborations have been financially supported by national as well as international research grants.

Besides having graduated around 150 undergraduate and master students, as well as 20 doctorates, he is currently supervising 10 students of doctor program and have totally produced around 500 working papers (articles, posters, books, chapters, scientific and academic reports).

He has also been active in scientific/professional communities: Indonesian Physical Society, Indonesian Magnetics Society (President, 2018-2020), Materials Research Society Indonesia, American Physical Society, American Association for Advancement of Science, International Association of Advanced Materials, Asia-Oceania Neutron Scattering Society (Executive Committee, 2016-2019).

Amorphous silicon (a-Si) and carbon (a-C) have received great attention for fundamental physics and potentially inexpensive solar cells. We produce a hydrogenated amorphous silicon (a-Si:H) and an a-C like films on indium tin oxide (ITO) generating photovoltaic cells with increasing efficiency. The a-Si:H films have been deposited from SiH4/H2 gases with various hydrogen content employing plasma enhanced chemical vapor deposition (PE-CVD). Meanwhile, we produce a new amorphous carbon (a‑C) like film from palmyra sap (biomass) using a nanospray technique. Spectroscopic ellipsometry supported with electron microscopy and synchrotron X-ray absorption spectroscopy is used to probe optical properties and the density of electronic states in the various crystallinity from nano-size crystals to amorphous a-Si, a-Si:H, a-C, a-C:B (p-type) and a-C:N (n-type) films. Our result shows the importance of exciton and plasmon coupling in determining efficiency of photovoltaic devices for all films. For the a-C case, the efficiency of photovoltaic effect exceeding three order of magnitude higher than the existing biomass‑derived a‑C has been achieved for a homo-junction p-i-n.