Excess carriers lifetime in InP single crystals: Radiative versus nonradiative recombination

Abstract

We present a comprehensive and systematic study of the minority and majority carrier lifetimes in InP single crystals doped in the range of 1×1015–4×1018 cm−3. Radiative recombination dominates in undoped InP, because the Shockley–Read–Hall lifetime is very long (>10 μs). For S or Sn doped n-type InP with intermediate doping concentration, nonradiative recombination is dominant under low injection conditions, hence the effective lifetime increases with increasing the injection level. On the other hand, the effective lifetime decreases with increasing the injection level under high excitation conditions due to radiative recombination. Thus, the effective lifetime has the largest value (140 ns for S-doped InP with majority carrier concentration n0=2×1017 cm−3, and 110 ns for Sn-doped InP with n0=3×1017 cm−3) for an injection level of around 1×1017 cm−3. Such information is important for the design of devices that operate under high injection levels like lasers and concentrated solar cells. In p-InP, nonradiative recombination and trapping dominate even in low doped samples and the effective lifetimes are much shorter than in n-InP.