Electrical characterization of the AIIIBV-N heterostructures by capacitance methods

Abstract

This paper highlights the electrical characterization of three types of the multiple quantum well (MQW) InGaAsN/GaAs heterostructures labelled NI58n, NI59n and NI66n with the nitrogen concentration of about 0.4% and indium content of 12.1%, 13.5% and 13.0%, respectively, using capacitance methods. These MQW InGaAsN/GaAs heterostructures were grown by atmospheric pressure metal organic vapour phase epitaxy (APMOVPE) at various growth conditions. The capacitance-voltage and DLTS measurements of these structures were performed utilizing the measurement system BIORAD DL8000.The CV characteristics measured at different temperatures on all heterostructures show very fine fluctuations of capacitance in the voltage range around 0V, which is suggested to be a result of free carriers’ emission from quantum wells. The absence of GaAs “cap” layer in one of the samples shifted its CV characteristic to lower values of capacity.According to the DLTS measurement it is highly probable that the similar system of defects is present in all samples. The presence of the deep level ET1 is clear in all samples and its parameters were calculated by multi level evaluation (the activation energy of the defect which is approx. ΔET=0.62eV, value of effective capture cross-section of the defect σT is about 10−16cm2, and defects concentration NT is about 1014cm−3).