Exciton Mott transition in Si Revealed by Terahertz Spectroscopy

Exciton Mott transition in Si is investigated by using terahertz time-domain spectroscopy. The excitonic correlation as manifested by the 1s-2p resonance is observed above the Mott density. The scattering rate of charge carriers is prominently enhanced at the proximity of Mott density, which is attributed to the non-vanishing exciton correlation in the metallic electron-hole plasma. Concomitantly, the signature of plasmon-exciton coupling is observed in the loss function spectra.Comment: 5 pages, 3 figure

Cooling Dynamics of Photoexcited Carriers in Si Studied by Using Optical Pump and Terahertz Probe Spectroscopy

We investigated the photoexcited carrier dynamics in Si by using optical pump and terahertz probe spectroscopy in an energy range between 2 meV and 25 meV. The formation dynamics of excitons from unbound e-h pairs was studied through the emergence of the 1s-2p transition of excitons at 12 meV (3 THz). We revealed the thermalization mechanism of the photo-injected hot carriers (electrons and holes) in the low temperature lattice system by taking account of the interband and intraband scattering of carriers with acoustic and optical phonons. The overall cooling rate of electrons and holes was numerically calculated on the basis of a microscopic analysis of the phonon scattering processes, and the results well account for the experimentally observed carrier cooling dynamics. The long formation time of excitons in Si after the above-gap photoexcitation is reasonably accounted for by the thermalization process of photoexcited carriers.Comment: 8 pages, 8 figures, to be published in Phys. Rev.

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Nabila Yasmine Talitha, Dr. Hanif Nur Widhiyanti, SH. M.Hum, Moch Zairul Alam, SH. MH. Fakultas Hukum Universitas Brawijaya Email :[email protected]    ABSTRAK Artikel ini membahas tentang Penggunaan Metode Right to Match didalam Tender Proses Pengadaan barang dan jasa, apakah sudah sesuai dengan Undang-undang Nomor 5 Tahun 1999 tentang Larangan Praktek Monopoli dan Persaingan Usaha Tidak Sehat, karena didalam praktik pelaksanaannya, Metode Right to Match berpotensi untuk menimbulkan peluang terjadunya persekongkolan Tender.Sekalipun telah terjadi perkembangan yang cukup berarti dalam sistem pengadaan selama ini, ada beberapa alasan utama mengapa sistem pengadaan belum berjalan dengan baik, pertama dasar hukum yang mengatur proses pengadaan barang dan jasa tidak diatur oleh perangkat perundang-undangan dengan tingkatan yang lebih tinggi, karena biasanya proses pengadaan hanya diatur oleh sebatas Keppres, sehingga akan menimbulkan dampak pada tingkat transparasi dan kejelasan perundangan tersebut, kedua, tidak adanya instansi tunggal yang berwenang untuk merumuskan kebijakan pengadaan barang dan jasa, ketiga adalah lemahnya kepatuhan kepada peraturan dan prosedur pengawasan pengadaan yang berlaku serta penegakan hukum.Selain ketiga hal diatas, masalah lain yang mengemuka adalah peraturan peraturan yang membatasi persaingan usaha di wilayah indonesia, sehingga melanggar prinsip suatu negara, satu pasar dan menghilangkan kesempatan yang timbul dalam persaingan yang sehat. Analisis ini dilakukan berdasarkan ketentuan-ketentuan yang ada didalam peraturan berkaitan dengan pengadaan barang da jasa dan peraturan perundang-undangan lain yang memiliki keterkaitan dengan metode Right to Match. Kata kunci: Right to Match, Pengadaan Barang/Jasa, Persaingan Usaha ABSTRACT This article discusses whether right-to-match method performed in the tender process of procurement is according to Law Number 5 of 1999 on the Prohibition of Monopoly Practices and Unhealthy Business Competition because the implementation of this method often triggers conflict in the tender process. Despite the fact that procurement system has improved, there are still several reasons why the procurement has not worked as expected. It is because the legal framework regulating procurement process is not supported by the provisions of Law and this process is mostly regulated by only Presidential Decree, leading to impact on transparency and clarity of the Law per se. Moreover, there is still no single institution that is authorized to set policy required in the procurement, followed by the minimum obedience towards regulation and procedures of procurement monitoring and legal enforcement. Another problem is related to the regulations which tend to restrict business competition in Indonesia. This breaks the principle in a country, in a market, and leads to unhealthy competition. This analysis was performed based on provisions of a related regulation of procurement and other Laws which are related to the right-to-match method. Keywords: Right to match, Procurement, Business Competition