Detection of Defect Density of States in Solution-Processed Quantum Devices

We report an electrical characterization technique to determine the defect density of states (DOS) in semiconductor nanoparticles without the interference of interface, and surface states. The state energies are determined by modulating the gate potential and injecting the charges to the specific quantum state. The density of charge in the energy state was detected from the shift of flatband voltage of the capacitance-voltage (CV) curve measured in less than 10μ s. The DOS spectrum has been measured for semiconductor CdTe quantum nanoparticles. The band gap of CdTe nanoparticle is calculated from DOS and found to be 1.67 eV, verified using optical absorption spectroscopy. The experimental result has been benchmarked using Sentaurus TCAD simulation.