Electrical characterization of the AIIIBV-N heterostructures by capacitance methods

• Published in: Applied surface science 2013-03, Vol.269, p.175-179
• Main Authors: Stuchlíková, Ľubica, Harmatha, Ladislav, Petrus, Miroslav, Rybár, Jakub, Šebok, Ján, Ściana, Beata, Radziewicz, Damian, Pucicki, Damian, Tłaczała, Marek, Kósa, Arpád, Benko, Peter, Kováč, Jaroslav, Juhász, Peter
• Format: Article
• Language: English
• Subjects: Capacitance voltage measurements; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Deep energy levels; Deep Level Transient Fourier Spectroscopy; Dilute nitrides; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; MQW InGaAsN/GaAs; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum wells; Schottky diodes; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties)
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2012.09.108

► Three MQW InGaAsN/GaAs heterostructures with various nitrogen ratios were compared. ► CV method and Deep Level Transient Spectroscopy measurements were used. ► Fluctuations in CV curves around 0V are due to free carriers’ emission from QW. ► DLTS shows that the similar system of defects is present in all samples. ► Multilevel evaluation confirmed the presence of deep level ET1 in all samples. 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).