Photoconductivity, carrier lifetime and mobility evaluation of GaAs films on Si (100) using optical pump terahertz probe measurements. (26th February 2019)

• Record Type: Journal Article
• Authors: Afalla, Jessica; Gonzales, Karl Cedric; Prieto, Elizabeth Ann; Catindig, Gerald; Vasquez, John Daniel; Husay, Horace Andrew; Tumanguil-Quitoras, Mae Agatha; Muldera, Joselito; Kitahara, Hideaki; Somintac, Armando; Salvador, Arnel; Estacio, Elmer; Tani, Masahiko
• Is Part Of: Semiconductor science and technology. Volume 34:Number 3(2019)
• Publication Date: 2019-02-26
• Subjects: GaAs on silicon -- terahertz spectroscopy -- photoconductivity; Semiconductors -- Periodicals; 621.38152
• DOI: 10.1088/1361-6641/ab0626
• Languages: English
• ISSNs: 0268-1242

Abstract

Abstract: The carrier lifetimes and electron mobility values were estimated for 2 μ m thick GaAs films grown on Si (100) substrates by means of optical pump terahertz probe (OPTP) technique. The GaAs/Si films measured were epitaxial grown at different substrate temperatures ( T S = 520 °C or T S = 630 °C). From x-ray diffraction measurements and Raman spectroscopy, the GaAs/Si films were shown to experience minimum strain at room temperature, and crystal misorientation in the (111) or (110) direction. With no measureable photoluminescence at room temperature, carrier lifetimes were measured via OPTP and found to be ∼20 and ∼35 ps for a fluence of ∼4 μ J cm −2, which is in the same order of magnitude as a reference bulk GaAs grown on SI–GaAs ( T S = 630 °C) having a lifetime of ∼70 ps. From OPTP photoconductivity measurements, the estimated GaAs/Si films' electron mobility are ∼2900 cm 2 V −1 s −1 ( T S = 520 °C) and ∼3500 cm 2 V −1 s −1 ( T S = 630 °C) at a pump-probe delay time of Δ t = 50 ps, in which the bulk GaAs electron mobility is ∼5200 cm 2 V −1 s −1 .