Concentration-dependent absorption and photoluminescence of n-type InP

Abstract

The absorption and photoluminescence of n‐type InP are examined as a function of free‐carrier concentration. It is found that concentration dependent band gap at 300 K is given by the empirical relation: E_g =1.344−(2.25±0.25)10⁻⁸n^1/3 (eV). The photoluminescence results are interpreted using the model taking into account nonparabolicity of the conduction band. Calculations of the peak position and photoluminescence line shape for band‐to‐band transitions are performed. Both the band filling as well as band tailing due to the Coulomb interaction of free carriers with ionized impurities and band shrinkage due to the exchange interaction between free carriers are considered in order to properly account for observed features of photoluminescence spectra. It is proposed that room temperature photoluminescence linewidth can be used for determination of the free carrier concentration in n‐type InP. This method can be used to estimate free carrier concentration ranging from 10¹⁶ to 10²⁰ cm⁻³.