Theoretical and experimental study of plasmonic effects in heavily doped gallium arsenide and indium phosphide

M Cada,J Pistora,K Postava,P Siroky,D Blazek

doi:10.1364/ome.5.000340

Abstract

Dispersion plasmonic interaction at an interface between a doped semiconductor and a dielectric is employed to use experimental data for determining the plasma frequency, the relaxation time, the effective mass, and the mobility of free electrons in heavily donor-doped gallium arsenide (GaAs) and indium phosphide (InP). A new solution for a plasmonic resonance at a semiconductor/dielectric interface found recently is exploited advantageously when analyzing the experimental data. Two independent measurement methods were used, namely the infrared reflectivity and the Raman scattering. Results indicate a good agreement with known data while pointing to some inaccuracies reported, and suggest a new alternative and accurate means to determine these important semiconductor parameters.

Highlights

Optical plasmons have been studied for many years [1]
The effect of free carriers on phonon damping, which we evaluated as 0.0089 for gallium arsenide (GaAs) and 0.0066 for indium phosphide (InP), is negligible since it yields values less than 0.01 for both doped GaAs and InP studied here
Since it is known that heavy n-doping of semiconductors causes their effective mass to increase due to the non-parabolic band, and even double over just an order of magnitude increase in concentration [21], our results are in a good agreement with published values

Summary

Introduction

Optical plasmons have been studied for many years [1]. The original gas plasmonic effects gave rise to interest in establishing similar electron gas collective oscillations in solid state materials. Intense research over the last decades yielded a number of interesting results as well as applications [2] Metals such as silver have shown to support strong plasmonic oscillations at optical frequencies along an interface with air or a dielectric. Since a semiconductor material can possess a higher background permittivity than that of the interfacing dielectric, the dispersion equation acquires a third solution, in addition to the well-known surface plasmonic and the bulk branches. The infrared reflectivity measurement and Raman scattering are well established methods [13] and were used in similar experiments [14] Their use in this work is a novel approach in that it combines the experimental data obtained from both independent methods with a new theoretical result in a unique way that enables one to determine the above mentioned important semiconductor parameters accurately and reliably

Theory

Experiment

Findings

Interpretation and discussion

Conclusion