Effect of thermal damage on optical and structural properties of In0.08Ga0.92N/In0.02Ga0.98N multi-quantum wells grown by MOCVD

Growth and characterization of the AlInGaN quaternary protective layer to suppress the thermal damage of InGaN multiple quantum wells

“…However, regardless of InGaN or AlInGaN protective layers, the peak wavelengths of PL emissions of InGaN MQWs with different protective layers were almost the same at 391.4 nm after hightemperature thermal treatment. Although the optical properties of InGaN MQWs were significantly dependent on the thermal treatment [9], InGaN MQWs structures capped by InGaN or AlInGaN protective layers did not show a large blue-shift of emission wavelength after thermal treatment. This means that both cap layers could play an effective role in suppressing the large blue-shift of emission peak by the significant out-diffusion of In atoms from the InGaN well.…”

“…In GaN-based light-emitting devices, the InGaN MQW active layer is easily deteriorated by thermal treatment during the hightemperature ramp-up process just after growing the InGaN active layer [9]. Since a high-quality AlInGaN quaternary epilayer can be achieved at the same growth temperature as the InGaN active layer, AlInGaN quaternary layers were introduced to suppress the thermal damage just after the growth of InGaN MQWs.…”

“…In the growth of the GaN-based LED/LDs structure, the high-temperature ramp-up process above 1000 1C is added to grow the p-type GaN layer just after the growth of the InGaN active layer below 800 1C. Due to the significant growth temperature difference of InGaN and GaN/AlGaN, the InGaN active layer would be degraded by thermal damage during the high-temperature rampup step [9]. It is necessary to suppress the thermal damage by introducing a protective layer, such as a GaN, InGaN or AlGaN layer.…”

Crystalline dependence of optical and interfacial properties of InGaN/GaN quantum wells on nonpolar a-plane GaN/r-sapphire

“…To suppress surface defects a-plane GaN films have been usually grown at relatively high temperature (41000 1C) and a low V/III ratio (o1000) to increase growth rate for directions of c+ and c À . However, InGaN QWs should have to be grown at relative low temperature ($ 800 1C) and high V/III ratio (41000) to increase In incorporation and NH 3 dissociation, respectively [13,14]. Because of these opposite growth conditions for a-plane GaN and InGaN, the surface defects could be easily generated by growth condition of a-plane InGaN QWs.…”

“…In general, high growth temperature ( 41000 1C) and low V/III were usually used to grow high quality a-plane GaN/r-sapphire [10][11][12]. However, the growth of InGaN active layer would require a relatively low growth temperature ( $ 800 1C) and high V/III because of high In volatility and low NH 3 dissociation rate, respectively [13,14]. Due to huge anisotropic crystallographic and growth parameters' difference between GaN and InGaN, it would give rise to crystal defects such as dislocation, stacking faults, and asymmetric V-defects during the growth of InGaN active layer [8][9][10][11][12], resulting in the significant optical and crystal degradation of InGaN/GaN QWs.…”