研究目的
To study voltage-induced charge redistribution in Cu(In,Ga)Se2 (CIGS) solar cell devices using high-speed capacitance-voltage profiling to understand the effects of deep defects on device instability and performance.
研究成果
HSCV measurements reveal that voltage-induced capacitance transients in CIGS devices are due to charge redistribution near the interface from high concentrations of deep defects (up to 10^17/cm3), which are temperature-dependent and can limit cell efficiency. These defects are prevalent across different fabricators and are a key performance-limiting factor.
研究不足
The method requires a sufficiently fast capacitance meter; the simulations assume constant defect concentrations, which may not hold in actual devices; distinguishing between static deep acceptors and metastable defects is difficult with voltage biasing alone; the study is limited to specific CIGS materials and may not generalize to all fabrication methods.
1：Experimental Design and Method Selection:
High-speed capacitance-voltage (HSCV) profiling was used to capture charge profile evolution after stepwise voltage changes, mimicking deep-level transient spectroscopy (DLTS) conditions. SCAPS device modeling was employed to simulate and interpret the results.
2：Sample Selection and Data Sources:
CIGS devices from three fabricators (MiaSolé Hi-Tech, National Renewable Energy Laboratory, and Institute of Energy Conversion) were evaluated, including full-stack and Schottky devices.
3：List of Experimental Equipment and Materials:
Janis cryostat with low-parasitic impedance probes, Sula DLTS spectrometer with custom software for HSCV, capacitance meter at 1 MHz frequency, LN2 cooling, HCl solution for etching, Al for Schottky contacts.
4：Experimental Procedures and Operational Workflow:
Devices were held in the dark; voltage steps from 0 to -1 V and vice versa were applied; HSCV sweeps were triggered at specified intervals (3 msec to 40 min) after voltage changes; measurements were conducted at temperatures from 280 to 320 K.
5：Data Analysis Methods:
Capacitance data were analyzed to calculate shallow doping profiles; SCAPS simulations optimized parameters like shallow and deep acceptor concentrations; integrated charge density and defect concentrations were derived from capacitance changes.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
