Temperature dependence of refractive indices of InP , GaAs , <mml:mrow…

We present the results of Fourier-transform measurements for determination of refractive indices of four semiconductor alloys in the midinfrared spectral range from 10 to 300 K. We investigate double-sided-polished, undoped <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:mrow><a:mi>In</a:mi><a:mi mathvariant="normal">P</a:mi></a:mrow></a:math> and <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><e:mrow><e:mi>Ga</e:mi><e:mi>As</e:mi></e:mrow></e:math> substrates as well as <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><h:msub><h:mi>In</h:mi><h:mrow><h:mn>0.53</h:mn></h:mrow></h:msub><h:msub><h:mi>Ga</h:mi><h:mrow><h:mn>0.47</h:mn></h:mrow></h:msub><h:mi>As</h:mi><h:mo>/</h:mo><h:mrow><h:mi>In</h:mi><h:mi mathvariant="normal">P</h:mi></h:mrow></h:math> and <l:math xmlns:l="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><l:mrow><l:mi>Al</l:mi><l:mi>As</l:mi></l:mrow><l:mo>/</l:mo><l:mrow><l:mi>Ga</l:mi><l:mi>As</l:mi></l:mrow></l:math> distributed Bragg reflector (DBR) mirrors with their operational wavelength designed for 4 µm. Through analysis of measured transmittance spectra supported by ellipsometry it is possible to determine the temperature-dependent refractive indices of <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><o:mrow><o:mi>In</o:mi><o:mi mathvariant="normal">P</o:mi></o:mrow></o:math> and <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><s:mrow><s:mi>Ga</s:mi><s:mi>As</s:mi></s:mrow></s:math> from 1.3 to 11 µm. Furthermore, by using reflectivity measurements supported by numerical modeling of the two types of designed DBR structures the refractive indices of <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><v:msub><v:mi>In</v:mi><v:mrow><v:mn>0.53</v:mn></v:mrow></v:msub><v:msub><v:mi>Ga</v:mi><v:mrow><v:mn>0.47</v:mn></v:mrow></v:msub><v:mi>As</v:mi></v:math> and <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><y:mrow><y:mi>Al</y:mi><y:mi>As</y:mi></y:mrow></y:math> for around 4 µm are determined with their temperature dependencies. Data acquired through this method could lead to improvement of already existing optical semiconductor devices expanding their application for longer wavelengths. Published by the American Physical Society 2024