<title>Photodiodes based on Pb<formula><inf><roman>1-x</roman></inf></formula>Sn<formula><inf><roman>x</roman></inf></formula>Se epitaxial films</title>

Abstract

The features of the electrical, optical and photoelectric properties ofgallium (Ga) doped Pb1SnSe epitaxial films (NGaO,5l at%) obtained by the molecular beam condensation method (MBC) are investigated. It is established that the interband absorption edge are stipulated from nondirect transition, the value of band gap (Eg), temperature coefficient of Eg are calculated. The conditions of preparing metal -Pb1SnSe photodiode structures are determined and capacity temperature dependence of metal -Pb1SnSe structure are analysed. The current-voltage and capacity -voltage characteristics ofthe obtained photodiodes.In the present work the features of electrophysical, optical and photoelectric properties based on Ga doped (0,5÷1 atM) Pb1SnSe epitaxial films, with thickness d=O,4÷2tm with purpose to obtain at T80K the high-resistance and specific conductivity o=l7÷3O Q' •cm', charge-carrier concentration p1,71O'6cm3 and mobility tl . 104cm2/VC are grown on BaF2(1 I 1) substrates by MBC the regime and tecknics of evaporation is descriptioned in [1,2]. The structural perfection, composition x and electrophisical parameters of films were supervised by electronographic methods, were determined from measurements of Hall effect at 77÷300 K and optical method by determination of the spectral dependence ofthe absorption coefficient in the region ofintrinsic absorption edge [3]. 3() L1 20 . /flc•V 4 (U ' 0,15 Fig. I Spectral dependence ofthe absorption coefficient of Pb093Sn007Se (curve 1) H Pb093Sn007Se <Ga> (curve 2) at T77K. For the p-Pb093Sn007Se <Ga, NGaO,45 aT.%> films with hole concentration p=2,8•1O'6÷1,2•1017cm3 (77K) in the long wave length of spectrum 13÷20 .im it was observed reflection minimum, which may be interpreted as plasma minimum [41. By the investigation of the p-Pb0 93Sn0 07Se <Ga> films optical properties it was found the decrease of transmission value T 2 ABSTRACT The features of the electrical, optical and photoelectric properties ofgallium (Ga) doped Pb1SnSe