Ion beam induced current analysis in GaN microwires

Abstract

GaN is a wide bandgap semiconductor which is expected to withstand high radiation doses. Consequently, it is considered a promising material for new generation particle detectors in radiation related applications. We report on the fabrication and electrical characterization under proton irradiation of single microwire sensors based on a back-to-back Schottky contact configuration. The microwires are grown by metal-organic vapor phase epitaxy and processed into sensors by using optical lithography on dispersed wires. We investigate the impact of the contacts and the semiconductor bulk on the ion beam induced current (IBIC) by irradiating specific areas of the sensor and simultaneously measuring the change in conductivity. We observed that the contribution of the excess charge carriers generated in the depletion regions formed at the contact interfaces is of low influence when compared to the excess charge carriers generated in the microwire bulk.

Self-powered proton detectors based on GaN core–shell p–n microwires

“…Recently, we demonstrated proton detection with radiaa) Electronic mail: dirkjanverheij@ctn.tecnico.ulisboa.pt tion sensors based on n-type GaN microwires. 24,25 Although showing good sensitivity and high absolute current signals, the long decay time and persistent ionocurrent as well as the fast decrease of the conductivity due to damage induced by the radiation are relevant setbacks. 24 Shifting from a conductive device to p-n junction based detectors leads to much faster response times as has been demonstrated in UV detectors based on GaN p-n junction microwires, 26 however, no such studies have been done using ionizing radiation.…”