Comparative Raman analysis of porous silicon DBRs before and after lift-off under visible and near-infrared laser excitation

Authors

Joybelle Lopez ⋅ PH Materials Science and Engineering Program, University of the Philippines Diliman
Horace Andrew Husay ⋅ PH National Institute of Physics, University of the Philippines Diliman
John Daniel Vasquez ⋅ PH Materials Science and Engineering Program, University of the Philippines Diliman
Al-Khadeem Ahmad ⋅ PH National Institute of Physics, University of the Philippines Diliman
Hiroshi Hojo ⋅ PH National Institute of Physics, University of the Philippines Diliman
Jarzen Kobe Fidelson ⋅ PH National Institute of Physics, University of the Philippines Diliman
Armando Somintac ⋅ PH National Institute of Physics, University of the Philippines Diliman

Abstract

Porous silicon (PSi) distributed Bragg reflectors (DBRs) were fabricated via electrochemical etching of arsenic-doped n-type Si (100) wafers, followed by lift-off to produce free-standing films (LO-DBR). The structural and vibrational properties of both DBR and LO-DBR were investigated using Raman spectroscopy under visible (532 nm) and near-infrared (785 nm) laser excitation. Under visible excitation, the DBR exhibited primary peak broadening and downshifting from 520 cm⁻¹ to 502 cm⁻¹ due to laser-induced thermal effects, accompanied by an oxide-related secondary peak shifting from 496 cm⁻¹ to 462 cm⁻¹. The LO-DBR showed enhanced thermal sensitivity with stabilization into amorphous Si-O phases. Near-infrared excitation revealed superior thermal stability for DBR/Si with primary peak position at 518 cm⁻¹ while LO-DBR exhibited progressive downshifting from 516 cm⁻¹ to 512 cm⁻¹, and broadening due to reduced heat dissipation. These results demonstrate how both substrate-supported DBR and free-standing LO-DBRs enable distinct approaches for thermally tunable photonic applications.

Issue

2025: Proceedings of the 43rd Samahang Pisika ng Pilipinas Physics Conference

Article ID

SPP-2025-PA-22

Section

Poster Session PA (Photonics, Condensed Matter, Materials and Quantum Science)

Published

2025-06-17

How to Cite

[1]

J Lopez, HA Husay, JD Vasquez, A-K Ahmad, H Hojo, JK Fidelson, and A Somintac, Comparative Raman analysis of porous silicon DBRs before and after lift-off under visible and near-infrared laser excitation, Proceedings of the Samahang Pisika ng Pilipinas 43, SPP-2025-PA-22 (2025). URL: https://proceedings.spp-online.org/article/view/SPP-2025-PA-22.