Heterostructures on InP substrate for high-speed detection devices over a large spectral range (0.8–1.6 μm)

Abstract

Semiconductor heterostructures of AIIIBV type with a bandgap adjustable by composition assure a good detection in a large spectral range of 0.8–1.6 μm, compatible with optical fibre communication spectral range. The paper presents the In0.53Ga0.47As/InP heterostructures, grown by Cl-VPE technique, and their use for fabrication of high-speed photodetectors as PIN photodiodes and Schottky barrier photodetectors. The PIN photodiodes have high value for responsivity, namely 0.3 A/W at 0.8 μm and 0.82 A/W at 1.3 μm wavelength without AR coating. The response time is 150 ps on 50 Ω load resistance, limited by RC constant. For Schottky barrier photodetectors metal sandwiches of Ni/Pd/Au, Ag/Pd/Au and Ti/Pd/Au were deposited on the heterostructures surface. The barrier height in the range (0.42–0.6) eV was obtained by growing a thin interlayer of n-InP over an n-type InGaAs/InP heterostructure. The responsivity of Schottky photodiodes was in the range 0.16–0.25 A/W and the response time under 100 ps.