Abstract:
In this work, in order to obtain highly doped germanium layers with donor impurity of antimony (Ge:Sb), promising for optoelectronic applications, the deposition of 200-nm thick Ge:Sb layers on a single-crystal $p$-Ge substrate was carried out by ion-beam sputtering followed by pulsed ion-beam treatment in the liquid-phase mode. The depth distribution of Sb atoms in Ge before and after pulsed treatment was studied by secondary ion mass spectrometry. The structural state of the Ge:Sb layers was studied by X-ray diffraction and Raman spectroscopy. The optical properties of Ge:Sb layers in the near and mid-IR region (1–10 microm) were investigated by measuring the transmission, reflection and photoluminescence at 300 K. The photoresponse of $n$-Ge:Sb/$p$-Ge diode structures was also studied at 300 K. It was found that pulsed ion-beam treatment in the melt mode leads to antimony diffusion into the Ge crystal to 1 microm, the formation of a single-crystal Ge:Sb layer with a tensile strain of 0.8%, a drop in sample transmittance to zero for $\lambda >$ 5 microm, the formation of a high electron concentration in the layer (1.5 $\cdot$ 10$^{20}$ cm$^{-3}$), an enhancement of the direct-band photoluminescence at $\lambda$ = 1.66 microm and to obtaining an extended photoresponse to about 2 microm.
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