A research team led by Profs.YANG Hui and CHEN Lianghui with the CAS Institute of Semiconductors (ISCAS) has made breakthrough progress in addressing key technological problems for the GaN-based laser diodes development. The research results were spoken highly at a panel meeting of experts held on 26 November in Beijing.

    As the third-generation semiconductor materials after silicon and GaAs, the GaN is noted for its wide band gap, and outstanding chemical and physical properties. It has a wide-range of application perspectives and high research value. The GaN-based laser devices are applicable to a variety of sectors, such as storage of optical information, full-color laser display, laser printing, atmospheric monitoring, underwater communications, two-color detection.

    With the support of CAS, Prof. Yang and his co-workers started the studies on the subject in April 2005. Thanks to the two-year-long hard work, they have made encouraging progress in dealing with a number of technical posers in the crystal growth, device processing and debugging. The background electron concentration of their materials is less than 5X1016/cm³ while the room-temperature electron mobility is kept at more than 900cm²/v-s, reaching the advanced international level. The hole concentration of P-type GaN reaches 5X1017 /cm³ with its resistance rate less than one Ω·cm.

    The ISCAS researchers took the lead in developing a GaN-based laser device capable of continuous wave operation at the room temperature with stripe width and length reaching 2.5μm and 800μm separately. The wavelength of the laser beam is 410nm with the threshold current down to 110 mA and its density 5.5kA/cm². When the working current is 150mA, the device has an output power up to 9.5mW, laying a solid foundation for the development of practical laser devices.

    The researchers have filed innovation patents for the design of the device's structure, crystal growth and the processing of the new laser elements. They have also published a dozen of research papers on the major journals both at home and abroad. At present, they are making efforts to develop a practical prototype of a 405nm blue-violet laser devices and a 450nm blue-green laser device in next three years.> />