Embedded structure as waveguide to improve the bandwidth of zero-bias UTC-PD in the millimeter-wave regime
Journal of Optics (India), 2026 (ESCI, Scopus)
- Yayın Türü: Makale / Tam Makale
- Basım Tarihi: 2026
- Doi Numarası: 10.1007/s12596-026-03193-0
- Dergi Adı: Journal of Optics (India)
- Derginin Tarandığı İndeksler: Emerging Sources Citation Index (ESCI), Scopus, Aerospace Database, Compendex, INSPEC, Materials Science & Engineering Collection (ProQuest), Technology Collection (ProQuest)
- Anahtar Kelimeler: Bandwidth, Electric field, Millimeter wave, Uni-traveling-Carrier Photodiodes (UTC-PD), Zero-bias
- Açık Arşiv Koleksiyonu: AVESİS Açık Erişim Koleksiyonu
- Bursa Uludağ Üniversitesi Adresli: Hayır
Özet
In this study, a new photodiode design and optimization method are proposed to significantly improve the bandwidth under zero-bias operation. A standard uni-traveling-carrier photodiode (UTC-PD) structure is used as a reference to benchmark a novel embedded-structure design with enhanced performance. The proposed configuration introduces an internal waveguide-like embedded geometry within the absorber and collector layers, which increases the device bandwidth and improves the frequency response while handling higher modulation rates. This is accomplished by redistributing and intensifying the internal electric field without an external bias. We demonstrate that adjusting the electric field profile in this manner can substantially increase the 3-dB bandwidth. In addition, the advantages of zero-bias operation are preserved and improved compared to those of a conventional photodiode design. Three different photodiode configurations are simulated in both 2D and 3D to evaluate their frequency response, band structure, and internal electric field distribution. According to the results, the proposed photodiode achieves roughly double the bandwidth of the reference design under zero-bias. Achieved through an embedded structure not explored in prior works, this improvement is promising for high-speed millimeter-wave communication and sensing systems, and represents a step toward sub-terahertz (THz) applications. Further scaling through device-area reduction and absorber-collector interface engineering is expected to extend operation into the sub-THz regime.