Temperature effect of ammonium halogenides as mineralizers on the phase stability of gallium nitride synthesized under acidic ammonothermal conditions

Photoluminescence from (0 0 0 1) GaN grown by the acidic ammonothermal technique

“…Although the PL intensity of the typically reported RL is independent of temperature [9], the intensity from our sample however decreased with increasing temperature. This behavior is similar to that reported for O-contaminated GaN [6]. The peak position decreases by almost 18 meV with the temperature rising from 10 to 150 K. The temperature dependence was different from that of the peaks near band edge.…”

“…A detailed description on the experimental routine has already been given elsewhere [4,6]. An autoclave with a Pt inner liner to prevent from corrosion was used for the growth.…”

“…We reported already that the handling of acidic mineralizer is relatively simple and that growth can be performed under considerably lower pressure and temperature [4,5]. A study on the effect of the acidic mineralizer on GaN growth performance supports the use of acidic mineralizers and the growth yield can be tuned upon modifying the acidity [6]. For long-term growth, we focus on the acidic mineralizer NH 4 Cl due to lower chemical activity than NH 4 Br or NH 4 I.…”

Physico-chemical features of the acid ammonothermal growth of GaN

“…exchanging Cl for Br and I in the formula for the mineralizer NH 4 Cl yields an increased lattice distorted GaN. It has been reported recently that a portion of cubic GaN phase was the highest when using NH 4 I and also increases towards lower process temperatures [5]. Later, a statement was found true for all the three mineralizers explored here.…”

“…Our experimental routine has recently been described in a greater detail [5]. We employ high-pressure autoclaves of 30 ml volume with a Pt inner liner so as to prevent from corrosion (Fig.…”