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

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 × 10 10 W -1 Hz 1/2 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. [ABSTRACT FROM AUTHOR]