GaN-based Single Crystal Optoelectronic Devices Epitaxial Growth And Metal-organic Chemical Vapor Deposition System

In 2014,three semiconductor scientists from Japan received the Nobel Prize in Physics for creating high power GaN based blue light emitting diode(LED).Since the invention of gallium nitride based LED,two decades have passed.It is becoming increasingly important that LED illumination technology is applied widely.Recently,according to an IEEE report,the free space visible light communication speed of a power-type single frequency GaN based blue LED approaches 3 Gb/s without pre-equalization.The novel GaN based blue LEDs with300 nm aluminum-doped zinc oxide transparent current spreading layer are applied to commercial products.LEDs are suitable for high date rate visible light communication.Where there is light,there is net.A GaN based blue LED with a diameter of 150 nm outputs the maximum optical power of 42 m W,demonstrating a 3 Gb/s free space data transmission speed.The modulation band width of communication reaches 600 MHz.Besides,AlGaN based deep ultraviolet light emitting diodes(DUV-LEDs)are applied widely,including the detection of biochemical reagents and sterilizations.AlGaN based solar detectors are applied to detect missiles and forest fires.Finally,metal organic chemical vapor deposition(MOCVD)systems of GaN based optoelectronics devices are emphasized.As an excellent GaN based optoelectronics devices epitaxy engineer,I will expound the following four parts:(1)Whole structure GaN based blue LED is grown on patterned sapphire substrate(PSS).The epitaxy methods and the analyses of material characterization of GaN-based blue LED are emphasized.Internal quantum efficiencies are optimised,so output power of LED reaches 100 m W under 3 V forward voltage.(2)AlGaN based deep ultraviolet light emitting diode(DUV-LED)grown on sapphire substrates is introduced.Firstly,AlN template is deposited on patterned sapphire substrate(PSS),then whole structure DUV-LED is deposited.Finally,AlGaN crystal properties are analysed.Output power reaches 3 mW under 20 mA current.(3)The high performance solar blind detector is deposited on AlGaN template,then the device layout is fabricated.The external quantum efficiency of solar blind detector of p-type-intrinsic-n-type(PIN)structure reaches 60% with 0 bias voltage,whereas the external quantum efficiency of solar blind detector of metal-semiconductor-metal(MSM)structure reaches 33% with 0 bias voltage.(4)From the perspective of the epitaxy engineer,the MOCVD systems are introduced,including water,gas and heater.It is emphasized that the induction-heating extreme-high-temperature(EHT)system is utilized as Al-rich AlGaN device growth.The engineering gas drawings are great value of engineering.The chamber structure drawings are explained in detail.