Diffusion capacitance

About: Diffusion capacitance is a research topic. Over the lifetime, 2427 publications have been published within this topic receiving 33948 citations.

Response to comment on "Resolving spatial and energetic distributions of trap states in metal halide perovskite solar cells"

Abstract: Ravishankar et al. claimed the drive-level capacitance profiling (DLCP) method cannot resolve trap density along depth direction in perovskites with given thickness, and explained the measured charges to be a consequence of geometrical capacitance and diffusion capacitance. We point out that the trap densities in DLCP method are derived from the differential capacitance at different frequencies, and thus the background charges caused by diffusion and geometry capacitance has been subtracted. Even for the non-differential doping analysis by DLCP, the contribution from diffusion capacitance is shown to be negligible and contribution from geometry capacitance is excluded. Additional experiment results further support the measured trap density represents the actual trap distribution in perovskite solar cells.

Bulk and metastable defects in CuIn1−xGaxSe2 thin films using drive-level capacitance profiling

Abstract: The drive-level capacitance profiling technique has been applied to ZnO/CdS/CuIn1−xGaxSe2/Mo solar cell devices, in order to study properties of defects in the CuIn1−xGaxSe2 film. Properties studied include the spatial uniformity, bulk defect response, carrier density, and light-induced metastable effects. These results indicate that previous estimates of carrier densities, from C–V profiling, may be significantly overestimated. In addition, a defect response previously thought to be located at the interface is observed to exist throughout the bulk material. Finally, an infrared light-soaking treatment is demonstrated to induce metastable changes in the bulk CuIn1−xGaxSe2 film. Hence, the drive-level capacitance profiling technique provides valuable insights into these films. Herein, the technique itself is fully explained, compared to other junction capacitance methods, and its utility is demonstrated using numerical simulation.

A charge-oriented model for MOS transistor capacitances

Abstract: A new model for computer simulation of capacitance effects in MOS transistors is presented. Transient currents are found directly from the charge distribution in the device rather than from capacitances. The effective capacitances which result are nonreciprocal. The model guarantees conservation of charge and includes bulk capacitances. Several circuit examples are considered.

Zero-voltage-switching multi-resonant technique-a novel approach to improve performance of high frequency quasi-resonant converters

Abstract: The power transistor in zero-current-switched quasiresonant converters (ZCS-QRCs) suffers from excessive voltage stress, and the converter regulation characteristics and stability are adversely affected by parasitic oscillations caused by the junction capacitance of the rectifying diode. A novel, multiresonant switch concept is proposed to overcome these problems. A unique multiresonant network arrangement results in absorption of all parasitic components, including transistor output capacitance, diode junction capacitance, and transformer leakage inductance, in the resonant circuit. This results in favorable switching conditions for all devices. Experimental results show that ZVS multiresonant converters are superior to ZVS-QRCs due to reduced transistor voltage stress and improved load range and stability. >

Quantum capacitance in nanoscale device modeling

Abstract: Expressions for the “quantum capacitance” are derived, and regimes are discussed in which this concept may be useful in modeling electronic devices. The degree of quantization is discussed for one- and two-dimensional systems, and it is found that two-dimensional (2D) metals and one-dimensional (1D) metallic carbon nanotubes have a truly quantized capacitance over a restricted bias range. For both 1D and 2D semiconductors, a continuous description of the capacitance is necessary. The particular case of carbon nanotube field-effect transistors (CNFETs) is discussed in the context of one-dimensional systems. The bias regime in which the quantum capacitance may be neglected when computing the energy band diagram, in order to assist in the development of compact CNFET models, is found to correspond only to the trivial case where there is essentially no charge, and a solution to Laplace’s equation is sufficient for determining a CNFET’s energy band diagram. For fully turned-on devices, then, models must include this capacitance in order to properly capture the device behavior. Finally, the relationship between the transconductance of a CNFET and this capacitance is revealed.