Transport mechanisms and effective Schottky barrier height of ZnO/a-Si:H and ZnO/μc-Si:H heterojunction solar cells

Abstract

The impact of boron doping on the p-layer of thin film silicon solar cells is assessed by measuring the effective Schottky barrier height of ZnO/a-Si:H and ZnO/μc-Si:H heterojunctions. A deviation from ideal diode characteristics is revealed by an increase of ideality factor with doping concentration. Higher current densities and lower effective Schottky barriers are evaluated for higher doping levels, resulting in increasingly Ohmic behaviour. This is attributed to an enhancement of tunneling through a thinner depletion region, as supported by computer simulations. Extracted barriers are in the range of 0.7–1 eV for the heterojunctions with rectifying behaviour.

Wide bandgap p-type nanocrystalline silicon oxide as window layer for high performance thin-film silicon multi-junction solar cells

“…It is well-known that an energy barrier for holes transport is generated between the front ZnO electrode and p-layer, which deteriorates the performance of a-Si:H solar cells [37,38]. To solve this problem, a front contact layer with high conductivity to enable tunneling transport of holes is inserted between the front TCO and the p-layer.…”

“…To solve this problem, a front contact layer with high conductivity to enable tunneling transport of holes is inserted between the front TCO and the p-layer. The p-doped nc-Si:H, nc-SiC:H and nc-SiO x layers have been demonstrated to be suitable for contact layer [37][38][39][40]. A wide bandgap of the contact layer is also favorable to reduce the optical absorption loss in the short wavelength region.…”

Origins of the Schottky Barrier to a 2DHG in a Au/Ni/GaN/AlGaN/GaN Heterostructure

“…Based on an effective mass of 0.16, we obtain a theoretical Richardson’s constant of 19.2 (Supporting Information D) and note that an error of 2 in A* results in an error of only 0.7 kT / q in Φ B . − From Figure (a), it is observed that the I – V characteristics plotted on a log–linear scale have significant nonlinearity, resulting in a temperature dependent ideality factor between 6–12 that we report here for the first time in this type of contact to a 2DHG in GaN. Figure (a) also shows a hypothetical curve with n = 1, whereas n > 1 is evidenced by the flattening of the I – V characteristic . Near to 0 V, there is little change of current with voltage; hence, n = 6–12 reflects the variation only due to T , in the term ( nkT ) in eq .…”

Achieving High Open‐Circuit Voltage for p‐i‐n Perovskite Solar Cells Via Anode Contact Engineering

“…Electrons can cross it without an energy barrier. However, in a p‐i‐n structure, the HTL having a large valence band maximum is directly contacted with the n‐type TCO, which may create an energy band misalignment and therefore deteriorate the photovoltage output and the fill factor (FF) …”