Optical and structural characterization of LTG-GaAs correlating excess As with THz emission

Miguel Yee Bacaoco; Elizabeth Ann P Prieto; Karl Cedric P Gonzales; Horace Andrew F Husay; John Daniel E Vasquez; Alexander E De Los Reyes; Maria Angela B Faustino; Arnel A Salvador; Armando S Somintac; Elmer S Estacio

Miguel Yee Bacaoco National Insitute of Physics, University of the Philippines Diliman
Elizabeth Ann P Prieto National Institute of Physics, University of the Philippines Diliman
Karl Cedric P Gonzales National Institute of Physics, University of the Philippines Diliman
Horace Andrew F Husay National Institute of Physics, University of the Philippines Diliman
John Daniel E Vasquez Materials Science and Engineering Program, University of the Philippines Diliman
Alexander E De Los Reyes National Institute of Physics, University of the Philippines Diliman
Maria Angela B Faustino Materials Science and Engineering Program, University of the Philippines Diliman
Arnel A Salvador National Institute of Physics, University of the Philippines Diliman
Armando S Somintac National Institute of Physics, University of the Philippines Diliman
Elmer S Estacio National Institute of Physics, University of the Philippines Diliman

Abstract

Optical and structural characteristics of in-house low-temperature-grown gallium arsenide (LTG-GaAs) grown at different substrate temperature (T_S) were investigated to determine their effects in the terahertz (THz) emission of the sample. Arsenic (As)-related defects in LTG-GaAs were shown to reduce the photoluminescence (PL) emission of the samples grown at lower T_S. The concentration of excess As atoms in LTG-GAs was calculated from the Raman spectra and was shown to be 1.64% and 2.50% for samples grown at T_S = 320°C and 270°C, respectively. The sample with higher concentration of excess As exhibited Raman spectra with narrow full width at half maximum attributed to larger As precipitate by finite particle size effect. The THz emission intensity of LTG-GaAs was observed to be significantly higher than the reference GaAs sample which proved that the presence of excess As in LTG-GaAs was effective in the enhancement of THz radiation.