Tuning the Plasmonic Response of AuGe Nanoparticles on GaAs Substrates: Implications for Photodetectors

Abstract

We present an integral study on the photonic response of AuGe nanoparticles (NPs) to establish a correlation between different parameters such as NP size, volume, and distribution over different substrates (n + GaAs, semiconducting GaAs) having different film thicknesses (∼5, ∼10 nm) at different annealing temperatures (573 and 673 K) subjected to repeated and stepped annealing cycles. The structural characterization of overlayer growth and formation of AuGe nanoclusters/ NPs is correlated with unusual plasmonic response measured during photonic characterization. The morphological changes induced by stepped annealing of the AuGe/GaAs system resulted in enhanced light emission and favorable tuning of plasmon frequency. A larger photoluminescence enhancement is measured with the fifth anneal, which is found to be related to the enhanced NP reflectance and is in good theoretical agreement with the Drude−Lorentz model. The numerical negative real permittivity "ε 1 " confirms the plasmonic impact, while X-ray photoelectron spectroscopy studies reveal the unique intermixing phenomena of AuGe and GaAs at the interface due to annealing. Additionally, ultrafast studies depict the periodic absorbance in the below-band-gap region of GaAs resembling an EL2-state-like behavior. The AuGe NPs embedded/adhered on a light-emitting surface thus offer both the ease and flexibility for tuning the plasmon resonance frequency, to attain tweaked and enhanced light-matter coupling, which can be concluded as plasmon-induced interfacial charge-transfer transition phenomena. The enhanced light coupling enhances both the photovoltaic conversion efficiency and quantum efficiency, thereby enabling increased solar cell fill factor and responsivity enhancement in photovoltaic devices such as photodetectors and thermal imagers.

Unveiling Electric Field Induced Ultrafast Charge Transfer Dynamics and Photoresponse Enhancement in Gold‐Interlayered Bi2Se3

“…[5][6][7][8][9][10][11] These studies have revealed unique photoresponse characteristics, including high photoresponsivity and ultrafast relaxation times, and it is also found that the occupied surface states often occur in the midgap of Bi 2 Se 3 , while unoccupied surface states emerge at higher energy levels, making Bi 2 Se 3 a promising candidate for optoelectronic applications. [12][13][14][15][16][17][18] Expanding on the potential of Bi 2 Se 3 and its surface states, the incorporation of a gold interlayer amidst topological layers may introduce an array of compelling functionalities. This interface not only influences and affects the surface charge density of the topological material but also modulates charge transfer dynamics.…”

Substrate-Dependent Ultrafast Charge-Carrier Dynamics: Unveiling the Annealing Effect on Optoelectronic Performance of Sb2Se3Thin Films

“…Ultrafast transient spectroscopy is the key tool that makes it simple to comprehend and visualize all of the aforementioned factors. − Carrier dynamics and recombination behavior of Sb 2 Se 3 in a single crystal and deposited thin films were examined in a series of studies undertaken by various researchers. Grad et al.…”

Revealing the Substrate Dependent Ultrafast Phonon Dynamics in Bi2Se3 Thin Films

“…[ 10 ] To determine the various type of EPI, different experimental and theoretical approaches are used to extract information about both the strength of the EPI and the energy of the involved phonons, such as angle‐resolved photoemission spectroscopy (ARPES), helium‐atom scattering, and Raman spectroscopy and ultrafast transient absorption spectroscopy (UFTS). [ 4,11 ] The ARPES is a fundamental technique that directly probes quasiparticle properties, while the time‐resolved ARPES or pump‐probe experiments access ultrafast carrier dynamics. [ 12–14 ] Richter et al.…”

“…[10] To determine the various type of EPI, different experimental and theoretical approaches are used to extract information about both the strength of the EPI and the energy of the involved phonons, such as angle-resolved photoemission spectroscopy (ARPES), helium-atom scattering, and Raman spectroscopy and ultrafast transient absorption spectroscopy (UFTS). [4,11] The ARPES is a fundamental technique that directly probes quasiparticle properties, while the time-resolved ARPES or pump-probe experiments access ultrafast carrier dynamics. [12][13][14] Richter et al investigated phonons of Bi 2 Se 3 , including phonon modes, for the first time using Raman spectroscopy while Irfan et al and Kim et al investigated the temperature-dependent frequency shift and linewidth of the A 2 1g and E 1g modes using Raman spectroscopy.…”