Epitaxial InGaAsP/InP photodiode for registration of InP scintillation

TL;DR

This paper presents a high-performance InGaAsP/InP photodiode integrated on an InP scintillator, capable of detecting individual alpha and gamma particles with low dark current and high sensitivity.

Contribution

The authors developed and characterized an epitaxially grown InGaAsP/InP photodiode directly on an InP scintillator, enabling efficient detection of scintillation light with low noise.

Findings

Low dark current of about 1 nA/cm² at 2 V bias

Successful detection of individual alpha and gamma particles

Demonstrated fast and sensitive scintillation readout

Abstract

Operation of semiconductor scintillators requires optically-tight integration of the photoreceiver system on the surface of the scintillator slab. We have implemented an efficient and fast quaternary InGaAsP pin photodiode, epitaxially grown upon the surface of an InP scintillator wafer and sensitive to InP luminescence. The diode is characterized by an extremely low room-temperature dark current, about 1 nA/cm2 at the reverse bias of 2 V. The low leakage makes possible a sensitive readout circuitry even though the diode has a large area (1 mm/times1 mm) and therefore large capacitance (50 pF). Results of electrical, optical and radiation testing of the diodes are presented. Detection of individual \alpha-particles and \gamma-photons is demonstrated.