Sulfide treatment of GaSb surface: influence on the LPE growth of InGaAsSb/AlGaAsSb heterostructures

The influence of Na2S and (NH4)(2)S treatments on the surface properties of GaSb have been investigated through the etch rate, ellipsometry and Schott ky barrier measurements. XRD and TEM analysis were performed to examine the effect of sulfide pretreatment of GaSb substrate on the LPE growth of InGa AsSb/AlGaAsSb heterostructures and their structural quality. Additionally, C-V characteristic of Hg-Schottky barriers were measured to evaluate carrie r concentrations in non-intentionally doped InGaAsSb epilayers. Na2S preepi taxial treatment has been applied to LPE growth of n-In0.084Ga0.916As0.086S b0.914/p-Al0.45Ga0.55As0.02Sb0.98 LED heterostructures for lambda(p) = 2.06 mu m and n-In0.23Ga0.77As0.18Sb0.82/p-Al0.24Ga0.76As0.02Sb0.98 PD heterost ructures for wavelength lambda = 2.0-2.4 mu m. As a result, LEDs which with increased by a factor of 4 quantum efficiency and total power of 6 mW were obtained. Mesa-structure photodiodes were characterised by detectivity D-l ambda=2.2 mu m* = 4 x 10(10) cmHz(1/2) W-1 at room temperature and dark cur rent density j(d) = 16 mA/cm(2) at a reverse bias of - 0.5 V. (C) 2000 Else vier Science Ltd. All rights reserved.