Nanoscale physics

Spectroscopic study of temperature dependent photoluminescence of GaAs1-xBix /GaAs heterostructures
Z.Ya. Zhuchenko1, G.G. Tarasov1, Yu.I. Mazur2, D.Fan3, S.-Q.Ju3 and G.J. Salamo2 
1 V.E. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, 41, Pr. Nauki, Kyiv, Ukraine,
 2 Institute for Nanoscience and Engineering, University of Arkansas, 731 W Dickson Street, Fayetteville, AR 72701, USA
3 Department of electrical Engineering, University of Arkansas, 3217 Bell Engineering Fayetteville, AR 72701, USA
E-mail: zhuchenko@isp.kiev.ua

Dilute bismides have attracted increasing interest due to a large band gap reduction  of ~90meV/% for GaAs1−xBix/GaAs temperature insensitive band gap, and large spin –orbit splitting. Typically these semiconductor heterostructures grown by molecular beam epitaxy technique are substantially disordered due to low temperature growth. In this work we used temperature dependent photoluminescence study of GaAs1−xBix/GaAs heterostructures with Bi concentration varying up to 4.6% in order to establish the peculiarities of temperature behavior of different excitonic and defect modes and their coupling. Thorough line shape analysis allows to establish energies of excitonic resonances and to trace their temperature evolution. 

Such approach explains the unusual behavior of the photoluminescence line width shown in Figure that is characterized by a strong reduction at highest  temperatures.