FT-DLTS studies on deep levels in InAs quantum dashes grown on InP

In this paper, we present a DLTS (Deep Level Transient Spectroscopy) study on InAs quantum dashes (QDas) grown by solid source molecular beam epitaxy on InP(001) substrates. These QDas are formed using the Stranski-Krastanow growth mode which undergoes from such strained epitaxy. The control of the growth conditions allows us to dispose of InAs QDas emitting at 1.55 μm. Isothermal capacitance/voltage (C-V-T) and transient capacitance spectroscopy measurements are performed to probe the temperature and electric-field dependence of the electron emission from charged QDas. Due to the high leakage current undergoing by the Schottky contact on the InP capped layer of our sample structure, only three energy levels have been found within the 10K-160K temperature range, at energies of 260 meV, 144 meV and 40 meV below the bottom edge of InP conduction band, respectively. This paper focuses on the study of the different mechanisms of emission process such as tunnelling mechanism and thermionic emission from the QDas confined states in order to identify the energy levels induced by these QDas.