Characterization of Cu(InGa)Se2 grain boundary properties by electron- and tip-probe methods

Inhomogeneities in Cu(In,Ga)Se2 Thin Films for Solar Cells: Band‐Gap Versus Potential Fluctuations

“…In addition to potential fluctuations due to excess charges at extended structural defects, experimental evidence has also been provided for fluctuating net doping values between neighboring grains and even between regions within individual grains . This phenomenon can be easily understood by regarding the large number of compensating (intrinsic or impurity‐related), shallow defects in the Cu(In,Ga)Se 2 thin film, which can be expected to be inhomogeneously distributed across the layer and which probably can be influenced substantially by the growth process of the Cu(In,Ga)Se 2 thin film.…”

“…In Refs. , the spatial variations in net doping can be extracted from distributions of the spreading resistance R across cross‐sectional specimens of Cu(In,Ga)Se 2 solar‐cell stacks, by using R = ( p 0 μ p e ) −1 , where μ p is the mobility of (free) holes in the Cu(In,Ga)Se 2 thin film. Since the resistance values are shown to differ by up to one order of magnitude between neighboring grains, the same would hold also for the (free) hole concentrations, when assuming constant hole mobilities across a Cu(In,Ga)Se 2 thin film.…”

Investigation of grain boundaries in BaSi2 epitaxial films on Si(1 1 1) substrates using transmission electron microscopy and electron-beam-induced current technique

“…For example, low-P GBs such as P 3 do not act as defect centers of minority carriers [16]. On the other hand, it is thought that recombination of carriers is suppressed by the local built-in potential at the GBs in the case of GBs in Cu(InGa)Se 2 [17]. However, there have been no reports thus far on GBs in BaSi 2 epitaxial films.…”

Potential variations around grain boundaries in impurity-doped BaSi2 epitaxial films evaluated by Kelvin probe force microscopy

“…Therefore, a lot of studies have been conducted on GBs in solar cell materials, such as polycrystalline Si and chalcopyrite semiconductors to improve efficiency. [13][14][15][16][17][18][19][20][21][22][23][24][25][26] One of the powerful tools for studying GBs properties is Kelvin probe force microscopy (KFM) method. Measurements with KFM yield the electrostatic properties of GBs and are used to determine the band diagrams across GBs.…”