Ultrafast photoresponse and enhanced photoresponsivity of Indium Nitride based broad band photodetector

•The first report on ultra-broadband (VIS-NIR), high responsive PD based on InN semiconductor operating at room temperature.•Highest reported photoresponsivity of 13.5 A/W, which is 30 times higher than the recently reported InN based photodetector.•Fabricated device exhibits very fast response time in microseconds, excellent stability and reliability with switching time.

InN direct band gap semiconductor is a promising material in the nitride family for high power and high frequency optoelectronic devices. However, the reports on photo-sensing ability of the material are limited with photoresponsivity < 1 A/W only. Here, we report fast photoresponse from high quality molecular beam epitaxy grown InN islands delivering photoresponsivity of 13.5 A/W, about 30 times higher than the recently reported InN based photodetector operating in the near infrared spectral range. The ultra-broadband response with high photoresponsivity from visible to near infrared spectral range is experimentally demonstrated. To the best of our knowledge, this study presents the working of a photodetector having fast response (38 μs) and high photo detectivity (5.5 × 1010 W-1 Hz1/2 cm) operating at room temperature. The device yields a quiet prompt saturation and decay under periodic illumination which demonstrate excellent stability and reliability of the device with switching time. The sub-linear dependent photocurrent on the bias voltage and incident power offers good tunability for multipurpose applications. This is the first report on ultra-broadband spectral range of InN based photodetectors that open up opportunities for developing the next generation high efficiency photodetectors.