Improvements on the electrical and luminescent properties of reactive molecular beam epitaxially grown GaN films by using AlN-coated sapphire substrates

Abstract

The electrical and luminescent properties of the GaN epitaxial films grown on AlN-coated sapphire by reactive molecular beam epitaxy have been studied. The GaN films on AlN epitaxial films have larger Hall mobilities and show more intense cathodoluminescence peaks at a wavelength of 360 nm than those of the GaN films grown directly on sapphire, which suggests that the crystal qualities of GaN films are improved by use of AlN-coated sapphire as substrates. The lattice matching and small difference of the thermal expansion coefficients between GaN and AlN are considered to result in the improvements.

Improved performance of GaN based light emitting diodes with ex-situ sputtered AlN nucleation layers

“…Due to the lack of natural GaN substrates, GaN-based LED structures are made typically on the (0001) c-plane sapphire substrates. 3,4 The interfacial energy difference between sapphire and GaN could cause large amount of dislocations and low crystal quality of the subsequently grown GaN layer. 5 The degraded quality of GaN layers presents intensive nonradiative recombination centers severely reducing the efficiency.…”

Background story of the invention of efficient blue InGaN light emitting diodes

“…1973 ±ÇÓÄÞÌ ÔËÐËÌ ÔÄÇÕÑAEËÑAE ®¥±-ÕËҠРÑÔÐÑÄÇ GaN, AEÑÒËÓÑÄÂÐÐÑÅÑ ÏÂÅÐËÇÏ [42] 1983 £ÞÔÑÍÑÍÂÚÇÔÕÄÇÐÐÞÌ GaN ÏÇÕÑAEÑÏ ®¿ Ô ËÔÒÑÎßÊÑÄÂÐËÇÏ ÃÖ×ÇÓ AlN [43] 1985 £ÞÔÑÍÑÍÂÚÇÔÕÄÇÐÐÞÌ GaN ÏÇÕÑAEÑÏ MOC-ÅËAEÓËAEÐÑÌ àÒËÕÂÍÔËË Ô ËÔÒÑÎßÊÑÄÂÐËÇÏ ÃÖ×ÇÓ AlN [6] 1989 GaN p-ÕËÒÂ Ô ËÔÒÑÎßÊÑÄÂÐËÇÏ°¯¿¿± (ÏÂÎÂâ ÍÑÐÙÇÐÕÓÂÙËâ AEÞÓÑÍ) [10] ±ÇÓÄÞÌ ÔÄÇÕÑAEËÑAE Ô ÑAEËÐÑÚÐÞÏ ÒÇÓÇØÑAEÑÏ Ä GaN 1991 ªÊÑÃÓÇÕÇÐËÇ AEÄÖØÒÑÕÑÍÑÄÑÌ MOC-ÅËAEÓËAEÐÑÌ àÒËÕÂÍÔËË [7] £ÞÓÂÜËÄÂÐËÇ GaN ÏÇÕÑAEÑÏ ®¿ Ô ËÔÒÑÎßÊÑÄÂÐËÇÏ ÃÖ×ÇÓ GaN [44] £ÞÔÑÍÑÍÂÚÇÔÕÄÇÐÐÞÌ GaN ÏÇÕÑAEÑÏ MOC-ÅËAEÓËAEÐÑÌ àÒËÕÂÍÔËË Ô ËÔÒÑÎßÊÑÄÂÐËÇÏ ÃÖ×ÇÓ GaN [9,45] ±ÇÓÄÞÇ ÐÇÒÓÇÓÞÄÐÞÇ ×ËÑÎÇÕÑÄÞÇ ÎÂÊÇÓÐÞÇ AEËÑAEÞ Ô ¥¤ Ë ®¬Á РÑÔÐÑÄÇ InGaN [29] ¬ÑÏÏÇÓÙËÂÎËÊÂÙËâ ÃÇÎÑÅÑ ÔÄÇÕÑAEËÑAEÂ Ô ËÔÒÑÎßÊÑÄÂÐËÇÏ ÔËÐÇÅÑ ÔÄÇÕÑAEËÑAEÂ Ô ¥¤ РÑÔÐÑÄÇ InGaN [27] . .…”

Examination of the temperature related structural defects of InGaN/GaN solar cells

“…The obtained tilt and the lateral mosaic dimensions are indicated in The hexagonal structured GaN shows high defect density when accumulated on different substrates like Al 2 O 3 , SiC and Si due to lattice inconsistency. These failures are dislocations and the main types of them [20,21] …”