Classification of Energy Levels in Quantum Dot Structures by Depleted Layer Spectroscopy

• Published in: Journal of electronic materials Vol. 39; no. 6; pp. 766 - 772
• Main Authors: Kaniewska, M., Engström, O., Kaczmarczyk, M.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Boston Springer US 01-06-2010; Springer; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Cross-disciplinary physics: materials science; rheology; DEEP LEVELS; deep-level transient spectroscopy; defect energy levels; ELECTRON TRAPS; Electronics and Microelectronics; Electrons; Exact sciences and technology; GAAS/GAAS; GROWTH TECHNIQUE; HETEROSTRUCTURES; Instrumentation; Materials Science; Nanoscale materials and structures: fabrication and characterization; Optical and Electronic Materials; Physics; Quantum confined energy levels; quantum dot; Quantum dots; Silicon carbide; Solid State Physics; Spectrum analysis; STATES; structures; TRANSIENT SPECTROSCOPY; defect energy levels; quantum dot structures; deep-level transient spectroscopy; Quantum confined energy levels; Gallium arsenides; Frequency dependence; Energy levels; Ground states; Tunnel effect; Quantum defect; Coexistence; Lamellar structure; Electron interaction; Electron emission; Defect states; Defect level; Quantum dots; DLTS; Excited states; Indium arsenides; III-V compound; Charge carrier trapping; Electronic structure; Nanostructured materials; III-V semiconductors
• ISSN: 0361-5235; 1543-186X; 1543-186X
• DOI: 10.1007/s11664-010-1125-4

The coexistence of quantum confined energy levels and defect energy levels in quantum dot (QD) structures may cause difficulties in distinguishing between their different origin when using deep-level transient spectroscopy (DLTS). Using InAs/GaAs QDs as demonstration vehicles, we present methodologies to obtain such a classification by DLTS. QD-related spectra measured as a function of repetition frequency of electrical pulses,
f
, or temperature,
T
, and reverse voltage,
V
R
, are depicted as contour plots on (
f
,
V
R
) and (
T
,
V
R
) planes, thus reflecting the complex thermal and tunneling emission of electrons from the ground and excited states. Defect-related levels give rise to different contour patterns and undergo modification, exhibiting double-peak structured emission when defects are agglomerated in the vicinity of the QD plane. This effect is interpreted in terms of an interaction between electron states in traps and the confined QD states.