Spectral response of n(+)-n-p and n(+)-p photodiodes

Semiconductor photodiodes with low dark current and high ultraviolet responsivity are needed in a number of applications. Neugroschel et al. (1978) have shown that the oxide-charge-induced electron accumulation type of high-low emitter (OCI-HLE) junction solar cells have higher maximum efficiency as compared to n(+)-p cells. It was suggested that this type of diode might have higher quantum efficiency in the blue region of the spectrum. The present paper has the objective to show that an optimized n(+)-p structure, which is simple to fabricate, can lead to a higher blue response as compared to the n(+)-n-p structure which involves a two-step process. Calculations show that the OCI-HLE diode has better spectral response than n(+)-p and n(+)-n-p diodes.