abstract

• We report on a rapid, 32-channel reflectance-difference (RD) spectrometer with sub-second spectra acquisition times and ΔRR sensitivity in the upper 10 -4 range. The spectrometer is based on a 50 kHz photo-elastic modulator for light polarization modulation and on a lock-in amplifier for signal harmonic analysis. Multichannel operation is allowed by multiplexing the 32 outputs of the spectrometer into the input of the lock-in amplifier. The spectrometer spans a wavelength range of 230 nm that can be tuned to cover E 1 and E 1 Δ 1 transitions for a number of III-V semiconductors at epitaxial growth temperatures, including GaAs, InAs, AlAs, and their alloys. We present two examples of real-time measurements to demonstrate the performance of the RD spectrometer, namely, the evolution of the RD spectrum of GaAs (001) annealed at 500 °C and the time-dependent RD spectrum during the first stages of the epitaxial growth of In 0.3Ga 0.7As on GaAs (001) substrates. © 2012 American Institute of Physics.

authors

• Armenta-Franco A.
• Balderas Navarro Raúl Eduardo
• Guevara Macías Liliana Estela
• Lastras Martínez Alfonso
• Lastras Martínez Luis Felipe
• Lastras Montaño Miguel Angel
• Núñez Olvera Oscar Fernando
• Ortega Gallegos Jorge

publication date

• 2012-01-01

funding provided via

• Consejo Nacional de Ciencia y Tecnología, CONACYT: 130009, 81316, 79635  Grant

published in

• Review of Scientific Instruments  Journal

keywords

• Acquisition time; GaAs; GaAs(001); II-IV semiconductors; InAs; Lock-in amplifier; Multichannel operation; Photo-elastic modulator; Polarization modulation; Real time measurements; Reflectance differences; Time resolution; Time-dependent; Wavelength ranges; Epitaxial growth; Gallium alloys; Gallium arsenide; Indium arsenide; Reflection; Semiconducting gallium; Semiconductor growth; Spectrometers; Spectrometry

Digital Object Identifier (DOI)

• 10.1063/1.4760252

start page

end page

volume

• 83

issue

• 10