Photostrictive behavior as the piezo-phototronic effect in InGaN/GaN multiple quantum wells

Recent progress of piezotronics and piezo-phototronics have not just uncovered new means to fine-tune/enhance the performances of GaN-based electronic/optoelectronic devices but also presented new perspectives on their applications. In this paper, with the combined use of Kelvin probe force microscopy and piezoresponse force microscopy, we demonstrate the photostrictive effect, that is the non-thermal light-induced strain in GaN samples with InGaN/GaN multiple quantum wells (MQWs) which can be elucidated through piezo-phototronic effect as the combination of light-induced surface electric field and converse piezoelectric effect. Such phenomenon is manifested by the enhancement in the effective piezoelectric coefficient along 33-mode d33eff of samples with In0.07Ga0.93N/GaN and In0.15Ga0.85N/GaN MQWs by 38.8% and 49.6%, respectively under the illumination of 405 nm laser light. Our results also suggest that their photostrictive performances can be tuned by manipulating the strain state of their MQWs which could be utilized for new generation of optomechanical sensors/actuators with adjustable photostrictive responses simply through externally applied strain.