Optical modelling of a-Si:H-based three-terminal three-colour detectors

Abstract Optical modelling of transparent conductive oxide (TCO1)/P–I1–N–I2–P/TCO2/P–I3–N/metal superstrate and substrate three-terminal three-colour detector assembly is performed. There are minor differences between superstrate and substrate structure. Simulations indicate that thickness variations of TCO1 layer have the largest effect on the short-wavelength spectral response (blue colour detection). For smooth SnO2:F as TCO1, the optimal thickness is estimated to be 130 nm. Analysis of N layer thickness shows that a thicker N layer ( d N >20 nm ) improves the blue/green colour separation, but also decreases spectral response to green colour. In the analysed structures, an optimal thickness of N layer is chosen to be 60 nm. Optimisation of TCO2 thickness decreases the sensitivity (with smaller interference fringes) of long-wavelength spectral response (red colour detection) on thickness variation of I3 layer. For smooth ZnO:Al as TCO2 the optimal thickness is ∼150 nm.