Parinaz Khaledi - Department of Physics, Azarbaijan Shahid Madani University, Tabriz, Iran
Mohammad Karimi - Department of Physics, Azarbaijan Shahid Madani University, Tabriz, Iran

— ІІ-VІ and ІІІ-V compound semiconductors with their advantageous physical and optical properties are important for optical and electronic devices. Semi -insulating GaAs is applied for high-frequency devices such as metal-semiconductor field-effect transistors (MESFETs), high-electron- mobility transistors (HEMTs), and HBTs (heterojunction-bipolar transistors). In fact, their main applications are for cellular phones and broadcasting-satellite(BS) systems. Conductive GaAs substrates are used for light-emitting diodes (LEDs), and for laser diodes (LDs) used for displays and CD players. Conductive GaP is a key material for yellow-green display LEDs. Conductive InP substrates are needed for LEDs, LDs and photodiodes (PDs) for optical-fiber communications. Semi-insulating InP is required for HEMTs and HBTs, exceeding GaAs-based devices, to be used for anticollision systems and millimeter-wave communications [1]. CdTe and CdZnTe substrates are used for HgCdTe epitaxial films for far-infrared detectors. Semi-insulating CdTe is applied for X-ray or gamma-ray detectors. Even ZnTe single crystals are now required for pure-green LEDs based on intrinsic p -n junctions [2] GaAs, InP and GaP have> 80% of the compound semiconductor market and are mainly grown by the liquid-encapsulated –Czochralski (LEC) method except for conductive GaAs, which is grown by the horizontal Bridgman (HB) method.

electronic, semiconductors, transistors