Asymmetrically contacted germanium photodiode using a metal-interlayer-semiconductor-metal structure for extremely large dark current suppression
| Autor: | Hyun Yong Yu, Hwan Jun Zang, Gwang Sik Kim, Yong Soo Choi, Gil Jae Park |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Materials science business.industry Schottky barrier chemistry.chemical_element Photodetector Germanium 01 natural sciences Atomic and Molecular Physics and Optics Cathode law.invention Anode Photodiode 010309 optics Optics Semiconductor chemistry law 0103 physical sciences Optoelectronics business Dark current |
| Zdroj: | Optics letters. 41(16) |
| ISSN: | 1539-4794 |
| Popis: | In this study, we proposed germanium (Ge) metal-interlayer-semiconductor-metal (MISM) photodiodes (PD), with an anode of a metal-interlayer-semiconductor (MIS) contact and a cathode of a metal-semiconductor (MS) contact, to efficiently suppress the dark current of Ge PD. We selected titanium dioxide (TiOsub2/sub) as an interlayer material for the MIS contact, due to its large valence band offset and negative conduction band offset to Ge. We significantly suppress the dark current of Ge PD by introducing the MISM structure with a TiOsub2/subinterlayer, as this enhances the hole Schottky barrier height, and thus acts as a large barrier for holes. In addition, it collects photo-generated carriers without degradation, due to its negative conduction band offset to Ge. This reduces the dark current of Ge MISM PDs by ×8000 for 7-nm-thick TiOsub2/subinterlayer, while its photo current is still comparable to that of Ge metal-semiconductor-metal (MSM) PDs. Furthermore, the proposed Ge PD shows ×6,600 improvement of the normalized photo-to-dark-current ratio (NPDR) at a wavelength of 1.55 μm. The proposed Ge MISM PD shows considerable promise for low power and high sensitivity Ge-based optoelectronic applications. |
| Databáze: | OpenAIRE |
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