Electrical characterization of InGaN/GaN quantum dots by deep level transient spectroscopy

Abstract

We have investigated the electrical property of InGaN quantum dots (QDs) embedded in GaN layer using capacitance-voltage and deep-level transient spectroscopy (DLTS) measurements. The apparent activation energy was observed 0.43 eV below the conduction band edge of barrier layers in InGaN/GaN QDs system. The capture barrier height of InGaN QDs was measured more than about 0.17 eV, showing the existence of strain between QDs and barrier layers. Thus, the bound state of QDs was estimated as 0.26 eV apart from the conduction band edge of the GaN.

Quantum confinement effects in gallium nitride nanostructures:ab initioinvestigations

“…[2] GaN nanodots have been synthesised experimentally by various methods, including colloidal dispersion, [6] ion implantation, [7,4] molecular beam epitaxy, [5] and metal-organic chemical vapour deposition. [8] One of the most notable aspects of quantum confinement in semiconductors is the nanostructure size dependence of the band gap; namely, the band gap increases as the size decreases. [9,10,11] Using a simple effective-mass approximation particle-in-a-box model (EMA-PIB) for confinement in planar wells, cylindrical wires, and spherical dots, the band gap compared to the bulk value depends linearly on 1/d 2 (where d is the diameter or thickness).…”

“…GaN nanodots have been synthesized experimentally by various methods, including colloidal dispersion [6], ion implantation [7,4], molecular beam epitaxy [5], and metal-organic chemical vapour deposition [8].…”

Study on Energy Band of InGaN/GaN Self-Assembled Quantum Dots by Deep-Level Transient Spectroscopy

“…10) Thus, it was considered that the E gan6 level originated from the GaN epilayer and that it might be related to an anti-site point defect. 11,12) On the other hand, the E gan2 and E gan8 signals seem to be located in similar measurement regions, and they might originate from N-vacancy defects or interface states. [11][12][13][14] Finally, the signal E gan4 was observed only in the InGaN QD structure and its magnitude was highest under 1.0 V pulse and À0:5 V measure bias conditions, which satisfies our expectations for the QD region.…”

“…11,12) On the other hand, the E gan2 and E gan8 signals seem to be located in similar measurement regions, and they might originate from N-vacancy defects or interface states. [11][12][13][14] Finally, the signal E gan4 was observed only in the InGaN QD structure and its magnitude was highest under 1.0 V pulse and À0:5 V measure bias conditions, which satisfies our expectations for the QD region. The E gan4 signal has very similar characteristics to signal A of our previous result.…”

“…The E gan4 signal has very similar characteristics to signal A of our previous result. 11) Arrhenius plots for the DLTS data are shown in Fig. 4, and a summary of the thermal activation energies and the emission cross sections of deep levels are shown in Table I.…”